First-principles study of structural, electronic, and magnetic properties at the (0001)Cr2O3−(111)Pt</…

We perform first-principles density functional calculations to elucidate structural, electronic, and magnetic properties at the interface of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mrow><a:mo>(</a:mo><a:mn>0001</a:mn><a:mo>)</a:mo></a:mrow><a:mrow><a:msub><a:mi>Cr</a:mi><a:mn>2</a:mn></a:msub><a:msub><a:mi mathvariant="normal">O</a:mi><a:mn>3</a:mn></a:msub></a:mrow><a:mo>−</a:mo><a:mrow><a:mo>(</a:mo><a:mn>111</a:mn><a:mo>)</a:mo></a:mrow><a:mi>Pt</a:mi></a:mrow></a:math> bilayers. This investigation is motivated by the fact that, despite the promise of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:msub><c:mi>Cr</c:mi><c:mn>2</c:mn></c:msub><c:msub><c:mi mathvariant="normal">O</c:mi><c:mn>3</c:mn></c:msub><c:mo>−</c:mo><c:mi>Pt</c:mi></c:mrow></c:math> heterostructures in a variety of antiferromagnetic spintronic applications, many key structural, electronic, and magnetic properties at the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mrow><e:msub><e:mi>Cr</e:mi><e:mn>2</e:mn></e:msub><e:msub><e:mi mathvariant="normal">O</e:mi><e:mn>3</e:mn></e:msub><e:mo>−</e:mo><e:mi>Pt</e:mi></e:mrow></e:math> interface are poorly understood. We first analyze all inequivalent lateral interface alignments to determine the lowest energy interfacial structure. For all lateral alignments including the lowest energy one, we observe an accumulation of electrons at the interface between <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mrow><g:msub><g:mi>Cr</g:mi><g:mn>2</g:mn></g:msub><g:msub><g:mi mathvariant="normal">O</g:mi><g:mn>3</g:mn></g:msub></g:mrow></g:math> and Pt. We find an unexpected reversal of the magnetic moments of the interface Cr ions in the presence of Pt compared to surface Cr moments in vacuum-terminated <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"><i:mrow><i:mrow><i:mo>(</i:mo><i:mn>0001</i:mn><i:mo>)</i:mo></i:mrow><i:mrow><i:msub><i:mi>Cr</i:mi><i:mn>2</i:mn></i:msub><i:msub><i:mi mathvariant="normal">O</i:mi><i:mn>3</i:mn></i:msub></i:mrow></i:mrow></i:math>. We also find that the heterostructure exhibits a magnetic proximity effect in the first three Pt layers at the interface with <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"><k:mrow><k:msub><k:mi>Cr</k:mi><k:mn>2</k:mn></k:msub><k:msub><k:mi mathvariant="normal">O</k:mi><k:mn>3</k:mn></k:msub></k:mrow></k:math>, providing a mechanism by which the anomalous Hall effect can occur in <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mrow><m:mrow><m:mo>(</m:mo><m:mn>0001</m:mn><m:mo>)</m:mo></m:mrow><m:mrow><m:msub><m:mi>Cr</m:mi><m:mn>2</m:mn></m:msub><m:msub><m:mi mathvariant="normal">O</m:mi><m:mn>3</m:mn></m:msub></m:mrow><m:mo>−</m:mo><m:mrow><m:mo>(</m:mo><m:mn>111</m:mn><m:mo>)</m:mo></m:mrow><m:mi>Pt</m:mi></m:mrow></m:math> bilayers. Our results provide the basis for a more nuanced interpretation of magnetotransport experiments on <o:math xmlns:o="http://www.w3.org/1998/Math/MathML"><o:mrow><o:mrow><o:mo>(</o:mo><o:mn>0001</o:mn><o:mo>)</o:mo></o:mrow><o:mrow><o:msub><o:mi>Cr</o:mi><o:mn>2</o:mn></o:msub><o:msub><o:mi mathvariant="normal">O</o:mi><o:mn>3</o:mn></o:msub></o:mrow><o:mo>−</o:mo><o:mrow><o:mo>(</o:mo><o:mn>111</o:mn><o:mo>)</o:mo></o:mrow><o:mi>Pt</o:mi></o:mrow></o:math> bilayers and should inform future development of improved antiferromagnetic spintronic devices based on the <q:math xmlns:q="http://www.w3.org/1998/Math/MathML"><q:mrow><q:msub><q:mi>Cr</q:mi><q:mn>2</q:mn></q:msub><q:msub><q:mi mathvariant="normal">O</q:mi><q:mn>3</q:mn></q:msub><q:mo>−</q:mo><q:mi>Pt</q:mi></q:mrow></q:math> material system. Published by the American Physical Society 2024