Structural characterization of amorphous YCrO3 from first principles
Identifieur interne : 002155 ( Istex/Corpus ); précédent : 002154; suivant : 002156Structural characterization of amorphous YCrO3 from first principles
Auteurs : Raquel Lizrraga ; Muhammad Ramzan ; Carlos Moyses Araujo ; Andreas Blomqvist ; Rajeev Ahuja ; Erik HolmstrmSource :
- Europhysics Letters [ 0295-5075 ] ; 2012-09.
Abstract
We perform a theoretical prediction of the structure of amorphous YCrO3. We obtained equivalent amorphous structures by means of two independent first principles density functional theory based methods: molecular dynamics and stochastic quenching. In our structural analysis we include radial and angle distribution functions as well as calculations of bond lengths and average coordination numbers. We find Cr3 atoms situated in slightly distorted oxygen octahedra throughout the amorphous structures and that the distribution of these octahedra is disordered. The presence of the same Cr3 local environments that give rise to ferroelectricity in the orthorhombic perovskite structure suggests that the amorphous phase of YCrO3 may also exhibit ferroelectric properties.
Url:
DOI: 10.1209/0295-5075/99/57010
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uniqKey="Araujo C" first="Carlos Moyses" last="Araujo">Carlos Moyses Araujo</name><affiliation><mods:affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</mods:affiliation></affiliation></author><author><name sortKey="Blomqvist, Andreas" sort="Blomqvist, Andreas" uniqKey="Blomqvist A" first="Andreas" last="Blomqvist">Andreas Blomqvist</name><affiliation><mods:affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</mods:affiliation></affiliation></author><author><name sortKey="Ahuja, Rajeev" sort="Ahuja, Rajeev" uniqKey="Ahuja R" first="Rajeev" last="Ahuja">Rajeev Ahuja</name><affiliation><mods:affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</mods:affiliation></affiliation></author><author><name sortKey="Holmstrm, Erik" sort="Holmstrm, Erik" uniqKey="Holmstrm E" first="Erik" last="Holmstrm">Erik Holmstrm</name><affiliation><mods:affiliation>Instituto de Ciencias Fsicas y Matemticas, Facultad de Ciencias, Universidad Austral de Chile Casilla 567, Valdivia, Chile</mods:affiliation></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">ISTEX</idno><idno type="RBID">ISTEX:AF88FBAF4E4D7CF19D5B3F8DD2806FA9BEBD375F</idno><date when="2012" year="2012">2012</date><idno type="doi">10.1209/0295-5075/99/57010</idno><idno type="url">https://api.istex.fr/document/AF88FBAF4E4D7CF19D5B3F8DD2806FA9BEBD375F/fulltext/pdf</idno><idno type="wicri:Area/Istex/Corpus">002155</idno></publicationStmt><sourceDesc><biblStruct><analytic><title level="a">Structural characterization of amorphous YCrO3 from first principles</title><author><name sortKey="Lizrraga, Raquel" sort="Lizrraga, Raquel" uniqKey="Lizrraga R" first="Raquel" last="Lizrraga">Raquel Lizrraga</name><affiliation><mods:affiliation>Instituto de Ciencias Fsicas y Matemticas, Facultad de Ciencias, Universidad Austral de Chile Casilla 567, Valdivia, Chile</mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail: raquellizarraga@uach.cl</mods:affiliation></affiliation></author><author><name sortKey="Ramzan, Muhammad" sort="Ramzan, Muhammad" uniqKey="Ramzan M" first="Muhammad" last="Ramzan">Muhammad Ramzan</name><affiliation><mods:affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</mods:affiliation></affiliation></author><author><name sortKey="Araujo, Carlos Moyses" sort="Araujo, Carlos Moyses" uniqKey="Araujo C" first="Carlos Moyses" last="Araujo">Carlos Moyses Araujo</name><affiliation><mods:affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</mods:affiliation></affiliation></author><author><name sortKey="Blomqvist, Andreas" sort="Blomqvist, Andreas" uniqKey="Blomqvist A" first="Andreas" last="Blomqvist">Andreas Blomqvist</name><affiliation><mods:affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</mods:affiliation></affiliation></author><author><name sortKey="Ahuja, Rajeev" sort="Ahuja, Rajeev" uniqKey="Ahuja R" first="Rajeev" last="Ahuja">Rajeev Ahuja</name><affiliation><mods:affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</mods:affiliation></affiliation></author><author><name sortKey="Holmstrm, Erik" sort="Holmstrm, Erik" uniqKey="Holmstrm E" first="Erik" last="Holmstrm">Erik Holmstrm</name><affiliation><mods:affiliation>Instituto de Ciencias Fsicas y Matemticas, Facultad de Ciencias, Universidad Austral de Chile Casilla 567, Valdivia, Chile</mods:affiliation></affiliation></author></analytic><monogr></monogr><series><title level="j">Europhysics Letters</title><idno type="ISSN">0295-5075</idno><idno type="eISSN">1286-4854</idno><imprint><publisher>EDP Sciences, IOP Publishing and Societ Italiana di Fisica</publisher><date type="published" when="2012-09">2012-09</date><biblScope unit="volume">99</biblScope><biblScope unit="issue">5</biblScope></imprint><idno type="ISSN">0295-5075</idno></series><idno type="istex">AF88FBAF4E4D7CF19D5B3F8DD2806FA9BEBD375F</idno><idno type="DOI">10.1209/0295-5075/99/57010</idno><idno type="href">http://stacks.iop.org/EPL/99/57010</idno><idno type="ArticleID">epl14836</idno></biblStruct></sourceDesc><seriesStmt><idno type="ISSN">0295-5075</idno></seriesStmt></fileDesc><profileDesc><textClass></textClass><langUsage><language ident="en">en</language></langUsage></profileDesc></teiHeader><front><div type="abstract">We perform a theoretical prediction of the structure of amorphous YCrO3. We obtained equivalent amorphous structures by means of two independent first principles density functional theory based methods: molecular dynamics and stochastic quenching. In our structural analysis we include radial and angle distribution functions as well as calculations of bond lengths and average coordination numbers. We find Cr3 atoms situated in slightly distorted oxygen octahedra throughout the amorphous structures and that the distribution of these octahedra is disordered. The presence of the same Cr3 local environments that give rise to ferroelectricity in the orthorhombic perovskite structure suggests that the amorphous phase of YCrO3 may also exhibit ferroelectric properties.</div></front></TEI><istex><corpusName>iop</corpusName><author><json:item><name>Raquel Lizrraga</name><affiliations><json:string>Instituto de Ciencias Fsicas y Matemticas, Facultad de Ciencias, Universidad Austral de Chile Casilla 567, Valdivia, Chile</json:string><json:string>E-mail: raquellizarraga@uach.cl</json:string></affiliations></json:item><json:item><name>Muhammad Ramzan</name><affiliations><json:string>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</json:string></affiliations></json:item><json:item><name>Carlos Moyses Araujo</name><affiliations><json:string>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</json:string></affiliations></json:item><json:item><name>Andreas Blomqvist</name><affiliations><json:string>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</json:string></affiliations></json:item><json:item><name>Rajeev Ahuja</name><affiliations><json:string>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</json:string></affiliations></json:item><json:item><name>Erik Holmstrm</name><affiliations><json:string>Instituto de Ciencias Fsicas y Matemticas, Facultad de Ciencias, Universidad Austral de Chile Casilla 567, Valdivia, Chile</json:string></affiliations></json:item></author><subject><json:item><lang><json:string>eng</json:string></lang><value>Letter</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>70 Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>71.23.Cq</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>71.55.Jv</value></json:item></subject><articleId><json:string>epl14836</json:string></articleId><language><json:string>eng</json:string></language><abstract>We perform a theoretical prediction of the structure of amorphous YCrO3. 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abbrev-type="publisher">EPL</abbrev-journal-title></journal-title-group><issn pub-type="ppub">0295-5075</issn><issn pub-type="epub">1286-4854</issn><publisher><publisher-name>EDP Sciences, IOP Publishing and Società Italiana di Fisica</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">epl14836</article-id><article-id pub-id-type="doi">10.1209/0295-5075/99/57010</article-id><article-id pub-id-type="manuscript">epl_14836</article-id><article-categories><subj-group subj-group-type="article-type"><subject>Letter</subject></subj-group><subj-group subj-group-type="section"><subject>70 Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties</subject></subj-group></article-categories><title-group><article-title>Structural characterization of amorphous YCrO<sub>3</sub> from first principles</article-title><alt-title alt-title-type="ascii">Structural characterization of amorphous YCrO<sub>3</sub> from first principles</alt-title><alt-title alt-title-type="short">Structural characterization of amorphous YCrO<sub>3</sub> from first principles</alt-title><alt-title alt-title-type="short-ascii">Structural characterization of amorphous YCrO<sub>3</sub> from first principles</alt-title></title-group><contrib-group content-type="all"><contrib contrib-type="author"><name><surname>Lizárraga</surname><given-names>Raquel</given-names></name><xref ref-type="aff" rid="epl14836af1">1</xref><xref ref-type="aff" rid="epl14836em1">(a)</xref></contrib><contrib contrib-type="author"><name><surname>Ramzan</surname><given-names>Muhammad</given-names></name><xref ref-type="aff" rid="epl14836af2">2</xref></contrib><contrib contrib-type="author"><name><surname>Araujo</surname><given-names>Carlos Moyses</given-names></name><xref ref-type="aff" rid="epl14836af2">2</xref></contrib><contrib contrib-type="author"><name><surname>Blomqvist</surname><given-names>Andreas</given-names></name><xref ref-type="aff" rid="epl14836af2">2</xref></contrib><contrib contrib-type="author"><name><surname>Ahuja</surname><given-names>Rajeev</given-names></name><xref ref-type="aff" rid="epl14836af2">2</xref></contrib><contrib contrib-type="author"><name><surname>Holmström</surname><given-names>Erik</given-names></name><xref ref-type="aff" rid="epl14836af1">1</xref></contrib><aff id="epl14836af1"><label>1</label>Instituto de Ciencias Físicas y Matemáticas, Facultad de Ciencias, <institution>Universidad Austral de Chile Casilla 567</institution>, Valdivia, <country>Chile</country></aff><aff id="epl14836af2"><label>2</label>Department of Physics and Astronomy, Division of Materials Theory, <institution>Uppsala University</institution> Box 516, SE-75120, Uppsala, <country>Sweden</country></aff><ext-link ext-link-type="email" id="epl14836em1">raquellizarraga@uach.cl</ext-link><author-comment content-type="short-author-list"><p>Raquel Lizárraga <italic>et al</italic>.</p></author-comment></contrib-group><pub-date pub-type="ppub"><month>9</month><year>2012</year></pub-date><pub-date pub-type="epub"><day>13</day><month>9</month><year>2012</year></pub-date><volume>99</volume><issue>5</issue><elocation-id content-type="artnum">57010</elocation-id><history><date date-type="received"><day>15</day><month>5</month><year>2012</year></date><date date-type="accepted"><day>10</day><month>8</month><year>2012</year></date></history><permissions><copyright-statement>Copyright © EPLA, 2012</copyright-statement><copyright-year>2012</copyright-year></permissions><self-uri xlink:href="http://stacks.iop.org/EPL/99/57010"></self-uri><abstract><title>Abstract</title><p>We perform a theoretical prediction of the structure of amorphous YCrO<sub>3</sub>. We obtained equivalent amorphous structures by means of two independent first principles density functional theory based methods: molecular dynamics and stochastic quenching. In our structural analysis we include radial and angle distribution functions as well as calculations of bond lengths and average coordination numbers. We find Cr<sup>+3</sup> atoms situated in slightly distorted oxygen octahedra throughout the amorphous structures and that the distribution of these octahedra is disordered. The presence of the same Cr<sup>+3</sup> local environments that give rise to ferroelectricity in the orthorhombic perovskite structure suggests that the amorphous phase of YCrO<sub>3</sub> may also exhibit ferroelectric properties.</p></abstract><kwd-group kwd-group-type="author-pacs"><kwd>71.23.Cq</kwd><kwd>71.55.Jv</kwd></kwd-group><counts><page-count count="6"></page-count></counts><custom-meta-group><custom-meta><meta-name>ccc</meta-name><meta-value></meta-value></custom-meta><custom-meta><meta-name>printed</meta-name><meta-value>Printed in France</meta-value></custom-meta></custom-meta-group></article-meta></front><body><sec id="epl14836s1"><title>Introduction</title><p>YCrO<sub>3</sub> is an interesting material for several reasons. It crystallizes in the orthorhombic perovskite structure (<italic>Pnma</italic>) [<xref ref-type="bibr" rid="epl14836bib01">1</xref>] and exhibits multiferroic behavior, that is, YCrO<sub>3</sub> displays simultaneously ferroelectricity [<xref ref-type="bibr" rid="epl14836bib02">2</xref>] and ferromagnetism [<xref ref-type="bibr" rid="epl14836bib03">3</xref>, <xref ref-type="bibr" rid="epl14836bib04">4</xref>] (canted antiferromagnetism). However, the development of electric polarization is inconsistent with the orthorhombic perovskite structure. Recently, it has been shown that although the average crystallographic structure above and below the dielectric transition is centrosymmetric, in the ferroelectric-like state, YCrO<sub>3</sub> is locally non-centrosymmetric where Cr is displaced 0.01 Å from its position along the <italic>z</italic>-direction [<xref ref-type="bibr" rid="epl14836bib01">1</xref>]. First principles calculations based on pseudopotentials and plane-wave basis set had also shown that a non-centrosymmetric structure is lower in energy than the orthorhombic structure [<xref ref-type="bibr" rid="epl14836bib02">2</xref>]. This new concept of “local non-centrosymmetry” may account for the weak ferroelectricity in YCrO<sub>3</sub>. The off-centering of the Cr atoms occurs in a disordered manner and therefore is local. Yet, the origin of the off-centering of the Cr atoms is not understood and hence, studies of local environments in the amorphous state, especially distortions of the oxygen octahedra that host the Cr<sup>+3</sup> cations are motivated since they may aid to elucidate these issues. Amorphous YCrO<sub>3</sub> (a-YCrO<sub>3</sub>) has been synthesized [<xref ref-type="bibr" rid="epl14836bib05">5</xref>], however it has not been experimentally characterized. We hope that the present work stimulates and encourages future experimental measurements on this material.</p><p>Amorphous materials are becoming increasingly interesting for industrial applications due to their mechanical and magnetic properties that are often superior to their crystalline counterparts. In general, the lack of periodicity and symmetries in amorphous structures make the interpretation of experiments very difficult. The structural information that can be obtained experimentally is the radial distribution function (RDF), an averaged quantity over the structure where detailed local environment information is missing. This is because, it is not possible to uniquely identify a structure by means of the RDF as in the case of crystals. One may in fact construct very different amorphous structures that fit the same RDF [<xref ref-type="bibr" rid="epl14836bib06">6</xref>].</p><p>To obtain local environment information one hence needs to produce an amorphous model structure and then compare its radial distribution function to measurements. It is of course possible to compare other calculated properties to experiments such as for example the X-ray photoemission spectrum (XPS) [<xref ref-type="bibr" rid="epl14836bib07">7</xref>, <xref ref-type="bibr" rid="epl14836bib08">8</xref>] and nuclear magnetic resonance (NMR) spectra [<xref ref-type="bibr" rid="epl14836bib09">9</xref>], the electronic density of states (DOS) [<xref ref-type="bibr" rid="epl14836bib10">10</xref>] or thermodynamic properties [<xref ref-type="bibr" rid="epl14836bib11">11</xref>]. The key then to obtain an amorphous structure which fits several independently measured properties is to have a reliable way to calculate it.</p><p>In this paper we aim to analyze the amorphous structure of a-YCrO<sub>3</sub> by performing first principles calculations by means of two different methods, namely, molecular dynamics (MD) and the stochastic quenching (SQ). The latter produces amorphous structures in a very simple and efficient way. The SQ approach has been successfully applied to simple monatomic amorphous metals [<xref ref-type="bibr" rid="epl14836bib12">12</xref>], metallic glasses [<xref ref-type="bibr" rid="epl14836bib11">11</xref>, <xref ref-type="bibr" rid="epl14836bib13">13</xref>], amorphous graphene [<xref ref-type="bibr" rid="epl14836bib14">14</xref>] and insulating amorphous systems [<xref ref-type="bibr" rid="epl14836bib09">9</xref>, <xref ref-type="bibr" rid="epl14836bib10">10</xref>]. We use two methods to obtain theoretically consistent amorphous structures since experimental data is not yet available. Radial and angle distribution functions, average coordination number and bond length are calculated and compared with those of the crystal.</p></sec><sec id="epl14836s2"><title>Theory</title><p>In the last decades MD [<xref ref-type="bibr" rid="epl14836bib15">15</xref>] has stood out as one of the most used methods to construct amorphous structures. Unfortunately, interaction potentials beyond pair-potentials are difficult to construct and the complex interactions in amorphous structures may need to be described by many-body interaction potentials. Such interaction potentials quickly become cumbersome when the system consists of many atomic species. <italic>Ab initio</italic> MD surpasses this problem by solving the electronic problem at each ionic step. This accurately produces the atomic forces used in the next ionic step but is much more time consuming than classical MD.</p><p>The SQ approach is a first principles method to produce amorphous structures very efficiently. In the SQ technique, <italic>N</italic> atoms are initially randomly distributed in a simulation box with a constraint that limits the closeness of approach of any pair. The atomic positions in the cell are subsequently relaxed until the forces on all atoms are sufficiently small. The relaxation is performed by a density functional theory (DFT) method. In this way, the amorphous structure is obtained with minimal computational effort.</p><sec id="epl14836s2-1"><title>Ab initio molecular dynamics</title><p>We constructed a 160-atoms supercell (32 yttrium, 32 chromium and 96 oxygen atoms) from the metastable cubic perovskite structure. A-YCrO<sub>3</sub> has been realized experimentally [<xref ref-type="bibr" rid="epl14836bib05">5</xref>], however, to our knowledge the density has not been determined so we used in the calculations the equilibrium volume at 0 K of a calculated cubic perovskite YCrO<sub>3</sub>, <italic>V</italic> =1733.6 Å<sup>3</sup> as a starting guess. This volume corresponds to a density of 5.71 g/cm<sup>3</sup>. The system was then heated up under NPT conditions at 6000 K until it undergoes a melting transition, loosing memory of the initial structure (forming the molten state). This was achieved after 10 ps of MD run (10000 1 fs ionic steps). Thereafter, we cooled down the system from 6000 to 300 K in 3 ps (3000 1 fs ionic steps). The last snapshot of this simulation was then optimized at 0 K to quench into the amorphous state. After optimization, the volume of the cell became 1946.2 Å<sup>3</sup>, which corresponds to a density of 5.15 g/cm<sup>3</sup>. For comparison, the density of the orthorhombic perovskite phase is 6.026 g/cm<sup>3</sup> [<xref ref-type="bibr" rid="epl14836bib16">16</xref>].</p></sec><sec id="epl14836s2-2"><title>Stochastic quenching procedure</title><p>The SQ procedure that we used was the following: we started by constructing an initial configuration of 160 atoms (32 yttrium, 32 chromium and 96 oxygen atoms) distributed randomly in a cubic box with a constraint that limits the closeness of approach of any pair (0.4 Å). The volume of the cell was fixed to 1946.2 Å<sup>3</sup> as in the MD simulation. The volume may also be calculated in the SQ approach, but since our aim is to compare structural properties, we simply fixed the volume to the already calculated MD result. The positions of the atoms in the initial configurations were then relaxed using a first principles DFT method until the forces on every atom were smaller than 10<sup>−5</sup> eV/Å.</p></sec></sec><sec id="epl14836s3"><title>Computational details</title><p>The Vienna <italic>ab initio</italic> Simulation Package [<xref ref-type="bibr" rid="epl14836bib17">17</xref>, <xref ref-type="bibr" rid="epl14836bib18">18</xref>] (VASP) together with the Perdew, Burke, and Ernzerhof (PBE) parametrization [<xref ref-type="bibr" rid="epl14836bib19">19</xref>] of the exchange-correlation functional was used for the calculations of both the <italic>ab initio</italic> MD and the SQ method. The eigenstates of the electron wave functions were expanded on a plane-waves basis set using pseudopotentials to describe the electron-ion interactions within the projector augmented-waves approach [<xref ref-type="bibr" rid="epl14836bib20">20</xref>] (PAW). The following electronic states 4s, 4p, 5s, and 4d were treated as valence for Y, 3p, 3d and 4s states for Cr and 2s, 2p states for O.</p><p>The convergence criterion for the electronic self-consistent cycle was fixed at 10<sup>−7</sup> eV per cell and the forces on all ions were smaller than 10<sup>−5</sup> eV/Å. We used a cutoff energy of 300 eV for the amorphous phases. Structural optimizations were performed by using a standard conjugate gradient method during the stochastic quenching procedure. All calculations are non-spin polarized.</p></sec><sec id="epl14836s4"><title>Results and discussions</title><sec id="epl14836s4-1"><title>Radial distribution functions</title><p>We have characterized the amorphous structures by means of the radial distribution function (RDF). In fig. <xref ref-type="fig" rid="epl14836fig1">1</xref> we show the partial radial distribution functions <italic>g</italic><sub>12</sub> for a-YCrO<sub>3</sub>, where 1 and 2 stand for atom type 1 and 2, respectively. The dashed and solid curves correspond to MD and SQ results, respectively. We can see in the figure that there is excellent agreement between both curves, particularly, the width and position of the first peak for all the RDFs. The exception is the RDF for Cr-Cr. In the upper-right graph, the first peak of <italic>g</italic><sub>Cr-Cr</sub> is very wide and split in two. These two peaks are positioned at approximately 2.2 Å and 3.4 Å in both methods, but the shape of these two peaks as calculated by MD and SQ differ. This wide first peak indicates weak Cr-Cr correlation and this may explain the slight disagreement between MD and SQ. The number of Cr atoms in the cells may be insufficient to describe such a weak correlation correctly and that may result in the jagged appearance of the first peak in the <italic>g</italic><sub>Cr-Cr</sub> in the MD and SQ results.</p><fig id="epl14836fig1" position="float"><label>Fig. 1:</label><caption id="epl14836fc1"><p>(Color online) Partial radial distribution functions. The dashed and solid curves correspond to RDFs calculated by MD and SQ, respectively.</p></caption><graphic id="epl14836f1_eps" content-type="print" xlink:href="epl14836f1_pr.eps"></graphic><graphic id="epl14836f1_online" content-type="online" xlink:href="epl14836f1_online.jpg"></graphic></fig><p>The MD and SQ curves are almost identical to each other in the graphs for <italic>g</italic><sub>Y-O</sub>, <italic>g</italic><sub>Cr-O</sub> and <italic>g</italic><sub>O-O</sub>. In the lower-right graph, there is a small peak at around 1.6 Å that can be seen in the SQ but not in the MD curve. This feature corresponds to a small presence of O-O pairs (6 atoms) in the SQ amorphous structure that have been found before in oxides, for example in a-Al<sub>2</sub>O<sub>3</sub> [<xref ref-type="bibr" rid="epl14836bib09">9</xref>, <xref ref-type="bibr" rid="epl14836bib10">10</xref>] and SiO<sub>2</sub> [<xref ref-type="bibr" rid="epl14836bib21">21</xref>]. For values of <italic>r</italic> greater than 5 Å the MD and SQ curves are quite similar. This is simply a consequence of the absence of long range order. It is worth mentioning that some of the features of the orthorhombic perovskite structure remain in the amorphous phase. For instance, the Cr-O peak at ∼2 Å in <italic>g</italic><sub>Cr-O</sub> [<xref ref-type="bibr" rid="epl14836bib01">1</xref>] in the orthorhombic perovskite structure can still be seen in our amorphous structures. This shows that if the local Cr environments are preserved in the amorphous phase there is a possibility that the amorphous phase also possesses interesting magnetic and ferroelectric properties.</p><p>We have also tested other implementations of Cr pseudopotential, <italic>e.g.</italic> pseudopotentials with 3d and 4s states regarded as valence states without any change in the <italic>g</italic><sub>Cr-Cr</sub>. The local density approximation plus <italic>U</italic> (<italic>LDA</italic> + <italic>U</italic>) was not tested because we performed magnetic calculations for crystalline YCrO<sub>3</sub> and the magnetic moments on Cr were well described using the generalized gradient approximation (GGA).</p><p>The distance to the minimum after the first peak in the partial distribution functions, <italic>R</italic><sub>12</sub>, where 1 and 2 correspond to atom type 1 and 2, respectively, is generally taken as a cutoff used in the integration of the first peak of the RDFs to determine coordination numbers. By a close inspection of fig. <xref ref-type="fig" rid="epl14836fig1">1</xref> we determined the following values, <italic>R</italic><sub>12</sub>, for MD (SQ): <italic>R</italic><sub>Y-Y</sub> = 4.8(4.7) Å, <italic>R</italic><sub>Y-Cr</sub> = 4.3(4.5) Å, <italic>R</italic><sub>Y-O</sub> = 3.0(3.0) Å, <italic>R</italic><sub>Cr-Cr</sub> = 4.26(4.26) Å, <italic>R</italic><sub>Cr-O</sub> = 2.3(2.4) Å and <italic>R</italic><sub>O-O</sub> = 3.6(3.5) Å. Because the first peak in the RDF for Cr-Cr is not well defined the choice for <italic>R</italic><sub>Cr-Cr</sub> was made at the second minimum of the RDF. We have used these values to calculate average coordination numbers. In table <xref ref-type="table" rid="epl14836t1">1</xref> we list these values for MD and SQ in which bold symbols correspond to the central atom. We have added for comparison coordination numbers for Y, Cr and O in the ideal cubic and orthorhombic perovskite structure (from ref. [<xref ref-type="bibr" rid="epl14836bib16">16</xref>]). The cubic perovskite structure is metastable and we obtained the equilibrium lattice constant <italic>a</italic> = 3.8 Å from an energy <italic>vs.</italic> volume DFT calculation. The values of the amorphous structures obtained by MD and SQ are in good agreement. In table <xref ref-type="table" rid="epl14836t1">1</xref> we see that while the symmetries are reduced (cubic <inline-formula><tex-math></tex-math><inline-graphic xlink:href="epl14836ieqn1.gif"></inline-graphic></inline-formula> orthorhombic <inline-formula><tex-math></tex-math><inline-graphic xlink:href="epl14836ieqn2.gif"></inline-graphic></inline-formula> amorphous) the Y atoms lose O neighbors, from 12 in the ideal cubic and 8 in the orthorhombic to 7 in the amorphous state. In the orthorhombic structure Cr is placed in an oxygen octahedron that tilts slightly from its position in the ideal cubic perovskite, however in the amorphous phase this octahedron distorts and looses one oxygen atom.</p><table-wrap id="epl14836t1" position="float"><label>Table 1.</label><caption id="epl14836tc1"><p>Average coordination numbers in the ideal cubic and orthorhombic perovskite structure and in the amorphous structure as calculated by MD and SQ. Bold symbols correspond to the central atom.</p></caption><table frame="hsides"><colgroup><col align="left"></col><col align="center"></col><col align="center"></col><col align="center"></col><col align="center"></col><col align="center"></col><col align="center"></col></colgroup><thead><tr><th>Perovskite</th><th align="center" colspan="2">Y</th><th align="center" colspan="2">Cr</th><th align="center" colspan="2">O</th></tr><tr><th></th><th>Cubic</th><th>Ortho</th><th>Cubic</th><th>Ortho</th><th>Cubic</th><th>Ortho</th></tr></thead><tbody><tr><td><bold>Y</bold></td><td>6</td><td>6</td><td>8</td><td>6</td><td>12</td><td>8</td></tr><tr><td><bold>Cr</bold></td><td>8</td><td>6</td><td>6</td><td>6</td><td>6</td><td>6</td></tr><tr><td><bold>O</bold></td><td>4</td><td>2.7</td><td>2</td><td>2</td><td>8</td><td>10</td></tr><tr><td>Amorphous</td><td align="center" colspan="2">Y</td><td align="center" colspan="2">Cr</td><td align="center" colspan="2">O</td></tr><tr><td></td><td>MD</td><td>SQ</td><td>MD</td><td>SQ</td><td>MD</td><td>SQ</td></tr><tr><td><bold>Y</bold></td><td>7.5</td><td>7.5</td><td>6.2</td><td>5.9</td><td>7.0</td><td>6.9</td></tr><tr><td><bold>Cr</bold></td><td>6.2</td><td>5.9</td><td>4.8</td><td>5.8</td><td>5.0</td><td>4.6</td></tr><tr><td><bold>O</bold></td><td>2.3</td><td>2.3</td><td>1.7</td><td>1.5</td><td>9.9</td><td>9.0</td></tr></tbody></table></table-wrap><p>The stable crystalline form of YCrO<sub>3</sub> is orthorhombic perovskite (space group <italic>Pnma</italic>), in which the Cr<sup>+3</sup> cations are placed in oxygen octahedra and the Y<sup>+3</sup> cations are found in 8-fold oxygen coordination sites [<xref ref-type="bibr" rid="epl14836bib16">16</xref>, <xref ref-type="bibr" rid="epl14836bib22">22</xref>]. This structure is a distortion of the ideal cubic perovskite (ABO<sub>3</sub> formula) that is commonly viewed as built up by corner-sharing octahedra hosting the B cations while the A cations are sitting in dodecahedral sites (see table <xref ref-type="table" rid="epl14836t1">1</xref>). Even further distortions of the cubic perovskite would result in a hexagonal <italic>P</italic>6<sub>3</sub><italic>cm</italic> structure in which the B and A cations occupy 5- and 7-fold oxygen coordination sites, respectively. It is interesting to note that Cr and Y have also average oxygen coordination ∼5 and 7 in our amorphous structures. These local environments may hence be viewed as distorted versions of their crystal counterparts in the amorphous structures. These distorted octahedra can be observed in fig. <xref ref-type="fig" rid="epl14836fig2">2</xref>. In the figure the distorted octahedra were taken from the MD amorphous structure (left-hand side panel) and the SQ amorphous structure (right-hand side panel). In table <xref ref-type="table" rid="epl14836t2">2</xref> we have listed average bond lengths. Here we also find excellent agreement between MD and SQ. In general the bond distances do not change much in the amorphous structure compared to same values in the crystals. We note, however, that the Y-Y, Y-Cr and O-O bond lengths are longer in the amorphous structure compared to the crystal and these pairs also have higher coordination numbers in table <xref ref-type="table" rid="epl14836t1">1</xref>.</p><fig id="epl14836fig2" position="float"><label>Fig. 2:</label><caption id="epl14836fc2"><p>(Color online) In the left-hand side panel: representation of Cr atoms (light blue balls) in 5- and 6-fold oxygen (red balls) coordination from an MD amorphous structure. In the right-hand side panel: representation of Cr atoms (light blue balls) in 5- and 6-fold oxygen (red balls) coordination from an SQ amorphous structure.</p></caption><graphic id="epl14836f2_eps" content-type="print" xlink:href="epl14836f2_pr.eps"></graphic><graphic id="epl14836f2_online" content-type="online" xlink:href="epl14836f2_online.jpg"></graphic></fig><table-wrap id="epl14836t2" position="float"><label>Table 2.</label><caption id="epl14836tc2"><p>Average bond lengths for the ideal cubic and orthorhombic perovskite and for the MD and SQ amorphous structures. The cutoffs were taken from the RDFs in fig. <xref ref-type="fig" rid="epl14836fig1">1</xref>.</p></caption><table frame="hsides"><colgroup><col align="left"></col><col align="center"></col><col align="center"></col><col align="center"></col><col align="center"></col><col align="center"></col><col align="center"></col></colgroup><thead><tr><th>Perovskite</th><th align="center" colspan="2">Y</th><th align="center" colspan="2">Cr</th><th align="center" colspan="2">O</th></tr></thead><tbody><tr><td></td><td>Cubic</td><td>Ortho</td><td>Cubic</td><td>Ortho</td><td>Cubic</td><td>Ortho</td></tr><tr><td>Y (Å)</td><td>3.8</td><td>3.81</td><td>3.29</td><td>3.18</td><td>2.69</td><td>2.41</td></tr><tr><td>Cr (Å)</td><td>3.29</td><td>3.18</td><td>3.8</td><td>3.8</td><td>1.90</td><td>1.98</td></tr><tr><td>O (Å)</td><td>2.69</td><td>2.41</td><td>1.90</td><td>1.98</td><td>2.69</td><td>2.85</td></tr><tr><td>Amorphous</td><td align="center" colspan="2">Y</td><td align="center" colspan="2">Cr</td><td align="center" colspan="2">O</td></tr><tr><td></td><td>MD</td><td>SQ</td><td>MD</td><td>SQ</td><td>MD</td><td>SQ</td></tr><tr><td>Y (Å)</td><td>3.91</td><td>3.86</td><td>3.56</td><td>3.60</td><td>2.39</td><td>2.36</td></tr><tr><td>Cr (Å)</td><td>3.56</td><td>3.60</td><td>3.21</td><td>3.17</td><td>1.96</td><td>1.93</td></tr><tr><td>O (Å)</td><td>2.39</td><td>2.36</td><td>1.96</td><td>1.93</td><td>2.98</td><td>2.93</td></tr></tbody></table></table-wrap><p>Table <xref ref-type="table" rid="epl14836t3">3</xref> lists the oxygen local environments of Y and Cr. It also includes data from the cubic and orthorhombic perovskite structures from ref. [<xref ref-type="bibr" rid="epl14836bib16">16</xref>]. In the amorphous phase, the Y cations are found preferentially surrounded by 7 oxygen neighbors (59.3(44)% for MD(SQ)), one less than in the orthorhombic structure. However, Y<sub>VI</sub>, Y<sub>VIII</sub>, Y<sub>IX</sub>environments are also present in smaller percentages; namely 19(34)%, 13(19)% and 6.3(3.1)%, respectively as calculated by MD(SQ). In the orthorhombic perovskite, Cr is located inside perfect oxygen octahedra that are connected by the corners, whereas in the amorphous state Cr is found, on average, as Cr<sub>V</sub> = 40.6(56)% (rectangular pyramid). The SQ method finds a small percentage of Cr<sub>VI</sub> = 6.3% whereas MD obtains a larger value Cr<sub>VI</sub> = 31.2% which indicates that the local Cr environments are more distorted in the SQ structure. By close inspection of both amorphous structures in fig. <xref ref-type="fig" rid="epl14836fig2">2</xref> one can indeed observe the oxygen polyhedra that in MD appear less distorted. The occurrence of 6-fold coordinated Cr atoms is more frequent in the structure generated by MD.</p><table-wrap id="epl14836t3" position="float"><label>Table 3.</label><caption id="epl14836tc3"><p>Y and Cr local environments in the ideal cubic and orthogonal perovskite structure (ref. [<xref ref-type="bibr" rid="epl14836bib16">16</xref>]) and in the amorphous state as calculated by MD and SQ. Cutoffs were obtained from the RDFs in fig. <xref ref-type="fig" rid="epl14836fig1">1</xref>. Roman numbers indicate oxygen coordination.</p></caption><table frame="hsides"><colgroup><col align="left"></col><col align="center"></col><col align="center"></col><col align="center"></col><col align="center"></col></colgroup><thead><tr><th></th><th>Cubic</th><th>Orthogonal</th><th align="center" colspan="2">Amorphous</th></tr><tr><th></th><th></th><th></th><th>MD</th><th>SQ</th></tr></thead><tbody><tr><td>Y<sub>VI</sub>(%)</td><td></td><td></td><td>19</td><td>34.3</td></tr><tr><td>Y<sub>VII</sub>(%)</td><td></td><td></td><td>59.3</td><td>44</td></tr><tr><td>Y<sub>VIII</sub>(%)</td><td></td><td>100</td><td>13</td><td>19</td></tr><tr><td>Y<sub>IX</sub>(%)</td><td></td><td></td><td>6.3</td><td>3.1</td></tr><tr><td>Y<sub>XII</sub>(%)</td><td>100</td><td></td><td></td><td></td></tr><tr><td>Cr<sub>III</sub>(%)</td><td></td><td></td><td>6.3</td><td>9.4</td></tr><tr><td>Cr<sub>IV</sub>(%)</td><td></td><td></td><td>21.9</td><td>28.1</td></tr><tr><td>Cr<sub>V</sub>(%)</td><td></td><td></td><td>40.6</td><td>56.3</td></tr><tr><td>Cr<sub>VI</sub>(%)</td><td>100</td><td>100</td><td>31.2</td><td>6.3</td></tr></tbody></table></table-wrap></sec><sec id="epl14836s4-2"><title>Angle distribution functions</title><p>In fig. <xref ref-type="fig" rid="epl14836fig3">3</xref>(a) we display the angle distribution functions (ADF) for a-YCrO<sub>3</sub>. The dashed and solid curves represent MD and SQ results, respectively. In fig. <xref ref-type="fig" rid="epl14836fig3">3</xref>(b) we have included the ADF for the cubic and orthorhombic perovskite crystals for comparison. The data in the crystal ADF are represented by Gaussian curves with standard deviation of 2 degrees so that the height of each Gaussian represents the number of angles found in one crystal unit cell. The cutoffs were taken from the RDFs as before. In fig. <xref ref-type="fig" rid="epl14836fig3">3</xref>(a) we notice that the agreement is very good between the MD and SQ methods. The largest difference may be found in the Cr-Cr-Cr ADF and this is probably due to the weak Cr-Cr correlation that was discussed earlier. Comparing fig. <xref ref-type="fig" rid="epl14836fig3">3</xref>(a) and (b) it is possible to identify the remnants of the crystal angles in the amorphous structures as broad peaks. A particularly interesting pair of angles are the O-Cr-O and Cr-O-Cr due to their presence in the oxygen cages surrounding Cr. The crystal O-Cr-O angles (that describe the inside of the cage) of 90° and 180° are also found in the amorphous state to a large extent indicating that Cr can be found in oxygen cages also in the amorphous structure. The Cr-O-Cr angle (that describe an angle that links two cages) is, however, not well preserved in the amorphous structures, indicating that the Cr centered oxygen cages are not ordered. The Cr-O-Cr angle is also important due to its role in the stabilization of an antiferromagnetic state in YCrO<sub>3</sub>through super-exchange interaction [<xref ref-type="bibr" rid="epl14836bib23">23</xref>]. The fact that the Cr-O-Cr angle is not preserved in our amorphous structures may indicate that the antiferromagnetic state may be difficult to realize in the amorphous phase. On the other hand, the 146° Cr-O-Cr angle from the orthogonal perovskite may be found in small quantities in both the MD and SQ amorphous structures, implying weak correlation between the Cr centered oxygen cages.</p><fig id="epl14836fig3" position="float"><label>Fig. 3:</label><caption id="epl14836fc3"><p>(Color online) (a) Angle distribution functions of the amorphous structures generated by MD (dashed line) and SQ (solid line). (b) Angle distribution functions for the cubic (dot-dashed line) and orthorhombic perovskite (full line) crystals.</p></caption><graphic id="epl14836f3_eps" content-type="print" xlink:href="epl14836f3_pr.eps"></graphic><graphic id="epl14836f3_online" content-type="online" xlink:href="epl14836f3_online.jpg"></graphic></fig></sec></sec><sec id="epl14836s5"><title>Conclusions</title><p>We performed a detailed structural analysis of a-YCrO<sub>3</sub>by means of RDFs, ADFs, bond lengths and average coordination numbers. The theoretical consistency of the amorphous structures was ensured by using two different <italic>ab initio</italic>methods, that is, MD and SQ. The structures obtained by the two methods are equivalent and the small differences that we can see in the RDF and ADF analysis are too small to distinguish from statistical fluctuations. One difference that we have found is the presence of three O-O pairs in the SQ structure whereas no such pair was found in the MD structure. In both amorphous structures we have found Cr atoms situated in oxygen octahedra that resemble the local Cr environment in the orthorhomic perovskite structure. The ADF analysis revealed that these octahedra are slightly distorted and distributed in a disordered way throughout the amorphous matrix. We find indications in all our calculated properties that the Cr<sup>+3</sup>local environment of the crystal is only slightly modified in the amorphous phase. This strongly suggests that the interesting properties of the crystalline state may also be present in the amorphous phase. This is very encouraging for future experimental studies of the magnetic and ferroelectric properties of this material.</p></sec></body><back><ack><title>Acknowledgments</title><p>EH and RL acknowledge support from FONDECYT projects 1120334 and 1110602 and also the supercomputer Ainil at the Institute of Physics of Universidad Austral de Chile. MR is very grateful for computer time at SNIC and UPPMAX. RA wishes to acknowledge support from the Swedish research council (VR).</p></ack><ref-list content-type="numerical"><title>References</title><ref id="epl14836bib01"><label>1</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Ramesha</surname><given-names>K.</given-names></name><name><surname>Llobet</surname><given-names>A.</given-names></name><name><surname>Proffen</surname><given-names>Th.</given-names></name><name><surname>Serrao</surname><given-names>C. R.</given-names></name><name><surname>Rao</surname><given-names>C. N. R.</given-names></name></person-group><year>2007</year><source>J. Phys.: Condens. Matter</source><volume>19</volume><elocation-id content-type="artnum">102202</elocation-id></element-citation></ref><ref id="epl14836bib02"><label>2</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Serrao</surname><given-names>C. R.</given-names></name><name><surname>Kundu</surname><given-names>A. K.</given-names></name><name><surname>Krupanidhi</surname><given-names>S. B.</given-names></name><name><surname>Waghmare</surname><given-names>U. V.</given-names></name><name><surname>Rao</surname><given-names>C. N. R.</given-names></name></person-group><year>2005</year><source>Phys. Rev. B</source><volume>72</volume><elocation-id content-type="artnum">220101(R)</elocation-id></element-citation></ref><ref id="epl14836bib03"><label>3</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Judin</surname><given-names>V. M.</given-names></name><name><surname>Sherman</surname><given-names>A. B.</given-names></name></person-group><year>1981</year><source>Solid State Comun.</source><volume>4</volume><fpage>661</fpage></element-citation></ref><ref id="epl14836bib04"><label>4</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Morishita</surname><given-names>T.</given-names></name><name><surname>Tsushima</surname><given-names>K.</given-names></name></person-group><year>1981</year><source>Phys. Rev. B</source><volume>24</volume><fpage>341</fpage></element-citation></ref><ref id="epl14836bib05"><label>5</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Kim</surname><given-names>J. H.</given-names></name><name><surname>Shin</surname><given-names>H.-S.</given-names></name><name><surname>Kim</surname><given-names>S.-H.</given-names></name><name><surname>Moon</surname><given-names>J.-H.</given-names></name><name><surname>Lee</surname><given-names>B.-T.</given-names></name></person-group><year>2003</year><source>Jpn. J. Appl. Phys.</source><volume>42</volume><fpage>575</fpage></element-citation></ref><ref id="epl14836bib06"><label>6</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Treacy</surname><given-names>M. M. J.</given-names></name><name><surname>Borisenko</surname><given-names>K.</given-names></name></person-group><year>2012</year><source>Science</source><volume>335</volume><fpage>950</fpage></element-citation></ref><ref id="epl14836bib07"><label>7</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Amézaga</surname><given-names>A.</given-names></name><name><surname>Holmström</surname><given-names>E.</given-names></name><name><surname>Lizárraga</surname><given-names>R.</given-names></name><name><surname>Menendez-Proupin</surname><given-names>E.</given-names></name><name><surname>Bartolo-Perez</surname><given-names>P.</given-names></name><name><surname>Giannozzi</surname><given-names>P.</given-names></name></person-group><year>2010</year><source>Phys. Rev. B</source><volume>81</volume><elocation-id content-type="artnum">014210</elocation-id></element-citation></ref><ref id="epl14836bib08"><label>8</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Lizárraga</surname><given-names>R.</given-names></name><name><surname>Holmström</surname><given-names>E.</given-names></name><name><surname>Amézaga</surname><given-names>A.</given-names></name><name><surname>Bock</surname><given-names>N.</given-names></name><name><surname>Peery</surname><given-names>T.</given-names></name><name><surname>Menendez-Proupin</surname><given-names>E.</given-names></name><name><surname>Giannozzi</surname><given-names>P.</given-names></name></person-group><year>2010</year><source>J. Mater. Sci.</source><volume>18</volume><fpage>5071</fpage></element-citation></ref><ref id="epl14836bib09"><label>9</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Lizárraga</surname><given-names>R.</given-names></name><name><surname>Holmström</surname><given-names>E.</given-names></name><name><surname>Parker</surname><given-names>C.</given-names></name><name><surname>Arrouvel</surname><given-names>C.</given-names></name></person-group><year>2011</year><source>Phys. Rev. B</source><volume>83</volume><elocation-id content-type="artnum">094201</elocation-id></element-citation></ref><ref id="epl14836bib10"><label>10</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Århammar</surname><given-names>C.</given-names></name><name><surname>Pietzsch</surname><given-names>A.</given-names></name><name><surname>Bock</surname><given-names>N.</given-names></name><name><surname>Holmström</surname><given-names>E.</given-names></name><name><surname>Araujo</surname><given-names>C. M.</given-names></name><name><surname>Gråsjö</surname><given-names>J.</given-names></name><name><surname>Zhao</surname><given-names>S.</given-names></name><name><surname>Green</surname><given-names>S.</given-names></name><name><surname>Peery</surname><given-names>T.</given-names></name><name><surname>Hennies</surname><given-names>F.</given-names></name><name><surname>Amerioun</surname><given-names>S.</given-names></name><name><surname>Föhlisch</surname><given-names>A.</given-names></name><name><surname>Schlappa</surname><given-names>J.</given-names></name><name><surname>Schmitt</surname><given-names>T.</given-names></name><name><surname>Strocov</surname><given-names>V. N.</given-names></name><name><surname>Niklasson</surname><given-names>G. A.</given-names></name><name><surname>Wallace</surname><given-names>D. C.</given-names></name><name><surname>Rubensson</surname><given-names>J.-E.</given-names></name><name><surname>Johansson</surname><given-names>B.</given-names></name><name><surname>Ahuja</surname><given-names>R.</given-names></name></person-group><year>2011</year><source>Proc. Natl. Acad. Sci. U.S.A.</source><volume>108</volume><fpage>6355</fpage></element-citation></ref><ref id="epl14836bib11"><label>11</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Bock</surname><given-names>N.</given-names></name><name><surname>Holmström</surname><given-names>E.</given-names></name><name><surname>Peery</surname><given-names>T. B.</given-names></name><name><surname>Lizárraga</surname><given-names>R.</given-names></name><name><surname>Chisolm</surname><given-names>E. D.</given-names></name><name><surname>De Lorenzi-Venneri</surname><given-names>G.</given-names></name><name><surname>Wallace</surname><given-names>D. C.</given-names></name></person-group><year>2010</year><source>Phys. Rev. B</source><volume>82</volume><elocation-id content-type="artnum">144101</elocation-id></element-citation></ref><ref id="epl14836bib12"><label>12</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Holmström</surname><given-names>E.</given-names></name><name><surname>Bock</surname><given-names>N.</given-names></name><name><surname>Peery</surname><given-names>T. B.</given-names></name><name><surname>Lizárraga</surname><given-names>R.</given-names></name><name><surname>De Lorenzi-Venneri</surname><given-names>G.</given-names></name><name><surname>Chisolm</surname><given-names>E. D.</given-names></name><name><surname>Wallace</surname><given-names>D. C.</given-names></name></person-group><year>2009</year><source>Phys. Rev. E</source><volume>80</volume><fpage>51111</fpage></element-citation></ref><ref id="epl14836bib13"><label>13</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Holmström</surname><given-names>E.</given-names></name><name><surname>Bock</surname><given-names>N.</given-names></name><name><surname>Peery</surname><given-names>T. B.</given-names></name><name><surname>Lizárraga</surname><given-names>R.</given-names></name><name><surname>De Lorenzi-Venneri</surname><given-names>G.</given-names></name><name><surname>Chisolm</surname><given-names>E. D.</given-names></name><name><surname>Wallace</surname><given-names>D. C.</given-names></name></person-group><year>2010</year><source>Phys. Rev. B</source><volume>82</volume><elocation-id content-type="artnum">024203</elocation-id></element-citation></ref><ref id="epl14836bib14"><label>14</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Holmström</surname><given-names>E.</given-names></name><name><surname>Fransson</surname><given-names>J.</given-names></name><name><surname>Eriksson</surname><given-names>O.</given-names></name><name><surname>Lizárraga</surname><given-names>R.</given-names></name><name><surname>Sanyal</surname><given-names>B.</given-names></name><name><surname>Bhandary</surname><given-names>S.</given-names></name><name><surname>Katsnelson</surname><given-names>M. I.</given-names></name></person-group><year>2011</year><source>Phys. Rev. B</source><volume>84</volume><elocation-id content-type="artnum">205414</elocation-id></element-citation></ref><ref id="epl14836bib15"><label>15</label><element-citation publication-type="book"><person-group person-group-type="author"><name><surname>Allen</surname><given-names>M. P.</given-names></name><name><surname>Tildesley</surname><given-names>D. J.</given-names></name></person-group><year>2004</year><source>Computer Simulation of Liquids</source><publisher-loc>Oxford</publisher-loc><publisher-name>Clarendon Press</publisher-name></element-citation></ref><ref id="epl14836bib16"><label>16</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Ardit</surname><given-names>M.</given-names></name><name><surname>Cruciani</surname><given-names>G.</given-names></name><name><surname>Dondi</surname><given-names>M.</given-names></name><name><surname>Merlini</surname><given-names>M.</given-names></name><name><surname>Bouvier</surname><given-names>P.</given-names></name></person-group><year>2010</year><source>Phys. Rev. B</source><volume>82</volume><elocation-id content-type="artnum">064109</elocation-id></element-citation></ref><ref id="epl14836bib17"><label>17</label><element-citation publication-type="preprint"><comment>VASP is a package for performing <italic>ab initio</italic>quantum-mechanical molecular dynamics (MD) using pseudopotentials and a plane-wave basis set (for details see <ext-link ext-link-type="uri" xlink:href="http://cms.mpi.univie.ac.at/vasp/">http://cms.mpi.univie.ac.at/vasp/</ext-link>)</comment></element-citation></ref><ref id="epl14836bib18"><label>18</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Kresse</surname><given-names>G.</given-names></name><name><surname>Furthmüller</surname><given-names>J.</given-names></name></person-group><year>1996</year><source>Phys. Rev. B</source><volume>54</volume><fpage>11169</fpage></element-citation></ref><ref id="epl14836bib19"><label>19</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Perdew</surname><given-names>J. P.</given-names></name><name><surname>Burke</surname><given-names>K.</given-names></name><name><surname>Ernzerhof</surname><given-names>M.</given-names></name></person-group><year>1996</year><source>Phys. Rev. Lett.</source><volume>77</volume><fpage>3865</fpage></element-citation></ref><ref id="epl14836bib20"><label>20</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Blöchl</surname><given-names>P. E.</given-names></name></person-group><year>1994</year><source>Phys. Rev. B</source><volume>50</volume><fpage>17953</fpage></element-citation></ref><ref id="epl14836bib21"><label>21</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Skuja</surname><given-names>L.</given-names></name></person-group><year>1998</year><source>J. Non-Cryst. Solids</source><volume>239</volume><fpage>16</fpage></element-citation></ref><ref id="epl14836bib22"><label>22</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Cruciani</surname><given-names>G.</given-names></name><name><surname>Matteucci</surname><given-names>F.</given-names></name><name><surname>Dondi</surname><given-names>M.</given-names></name><name><surname>Baldi</surname><given-names>G.</given-names></name><name><surname>Barzanti</surname><given-names>A.</given-names></name></person-group><year>2005</year><source>Z. Kristallogr.</source><volume>220</volume><fpage>930</fpage></element-citation></ref><ref id="epl14836bib23"><label>23</label><element-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Ray</surname><given-names>N.</given-names></name><name><surname>Waghmare</surname><given-names>U. V.</given-names></name></person-group><year>2008</year><source>Phys. Rev. B</source><volume>77</volume><elocation-id content-type="artnum">134112</elocation-id></element-citation></ref></ref-list></back></article></istex:document></istex:metadataXml><mods version="3.6"><titleInfo><title>Structural characterization of amorphous YCrO3 from first principles</title></titleInfo><titleInfo type="alternative" contentType="CDATA"><title>Structural characterization of amorphous YCrO3 from first principles</title></titleInfo><name type="personal"><namePart type="given">Raquel</namePart><namePart type="family">Lizrraga</namePart><affiliation>Instituto de Ciencias Fsicas y Matemticas, Facultad de Ciencias, Universidad Austral de Chile Casilla 567, Valdivia, Chile</affiliation><affiliation>E-mail: raquellizarraga@uach.cl</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Muhammad</namePart><namePart type="family">Ramzan</namePart><affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Carlos Moyses</namePart><namePart type="family">Araujo</namePart><affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Andreas</namePart><namePart type="family">Blomqvist</namePart><affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Rajeev</namePart><namePart type="family">Ahuja</namePart><affiliation>Department of Physics and Astronomy, Division of Materials Theory, Uppsala University Box 516, SE-75120, Uppsala, Sweden</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Erik</namePart><namePart type="family">Holmstrm</namePart><affiliation>Instituto de Ciencias Fsicas y Matemticas, Facultad de Ciencias, Universidad Austral de Chile Casilla 567, Valdivia, Chile</affiliation><role><roleTerm type="text">author</roleTerm></role></name><typeOfResource>text</typeOfResource><genre type="brief-communication" displayLabel="rapid-communication"></genre><subject><genre>article-type</genre><topic>Letter</topic></subject><subject><genre>section</genre><topic>70 Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties</topic></subject><originInfo><publisher>EDP Sciences, IOP Publishing and Societ Italiana di Fisica</publisher><dateIssued encoding="w3cdtf">2012-09</dateIssued><dateCreated encoding="w3cdtf">2012-09-13</dateCreated><copyrightDate encoding="w3cdtf">2012</copyrightDate></originInfo><language><languageTerm type="code" authority="iso639-2b">eng</languageTerm><languageTerm type="code" authority="rfc3066">en</languageTerm></language><physicalDescription><internetMediaType>text/html</internetMediaType></physicalDescription><abstract>We perform a theoretical prediction of the structure of amorphous YCrO3. We obtained equivalent amorphous structures by means of two independent first principles density functional theory based methods: molecular dynamics and stochastic quenching. In our structural analysis we include radial and angle distribution functions as well as calculations of bond lengths and average coordination numbers. We find Cr3 atoms situated in slightly distorted oxygen octahedra throughout the amorphous structures and that the distribution of these octahedra is disordered. The presence of the same Cr3 local environments that give rise to ferroelectricity in the orthorhombic perovskite structure suggests that the amorphous phase of YCrO3 may also exhibit ferroelectric properties.</abstract><subject><genre>author-pacs</genre><topic>71.23.Cq</topic><topic>71.55.Jv</topic></subject><relatedItem type="host"><titleInfo><title>Europhysics Letters</title></titleInfo><genre type="journal">journal</genre><identifier type="ISSN">0295-5075</identifier><identifier type="eISSN">1286-4854</identifier><identifier type="PublisherID">epl</identifier><part><date>2012</date><detail type="volume"><caption>vol.</caption><number>99</number></detail><detail type="issue"><caption>no.</caption><number>5</number></detail><extent unit="pages"><total>6</total></extent></part></relatedItem><identifier type="istex">AF88FBAF4E4D7CF19D5B3F8DD2806FA9BEBD375F</identifier><identifier type="DOI">10.1209/0295-5075/99/57010</identifier><identifier type="href">http://stacks.iop.org/EPL/99/57010</identifier><identifier type="ArticleID">epl14836</identifier><accessCondition type="use and reproduction" contentType="copyright">Copyright EPLA, 2012</accessCondition><recordInfo><recordContentSource>IOP</recordContentSource></recordInfo></mods></metadata><serie></serie></istex></record>Pour manipuler ce document sous Unix (Dilib)
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