Promoting <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>p</mml:mi></mml:math>-based Hall effects by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi><mml:mtext>−</mml:mtext><mml:mi>d</mml:mi><mml:mtext>−</mml:mtext><mml:mi>f</mml:mi></mml:mrow></mml:math> hybridization in Gd-based dichalcogenides

Abstract

We conduct a first-principles study of Hall effects in rare-earth dichalcogenides, focusing on monolayers of the H-phase <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi>Eu</a:mi><a:msub><a:mi>X</a:mi><a:mn>2</a:mn></a:msub></a:mrow></a:math> and <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mi>Gd</b:mi><b:msub><b:mi>X</b:mi><b:mn>2</b:mn></b:msub></b:mrow></b:math>, where <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mi>X</c:mi><c:mo>=</c:mo><c:mi mathvariant="normal">S</c:mi></c:mrow></c:math>, Se, and Te. Our predictions reveal that all <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mrow><e:mi>Eu</e:mi><e:msub><e:mi>X</e:mi><e:mn>2</e:mn></e:msub></e:mrow></e:math> and <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:mi>Gd</f:mi><f:msub><f:mi>X</f:mi><f:mn>2</f:mn></f:msub></f:mrow></f:math> systems exhibit high magnetic moments and wide band gaps. We observe that while in the case of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mrow><g:mi>Eu</g:mi><g:msub><g:mi>X</g:mi><g:mn>2</g:mn></g:msub></g:mrow></g:math> the <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"><h:mi>p</h:mi></h:math> and <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"><i:mi>f</i:mi></i:math> states hybridize directly below the Fermi energy, the absence of <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"><j:mi>f</j:mi></j:math> and <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"><k:mi>d</k:mi></k:math> states of Gd at the Fermi energy results in the <l:math xmlns:l="http://www.w3.org/1998/Math/MathML"><l:mi>p</l:mi></l:math>-like spin-polarized electronic structure of <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mrow><m:mi>Gd</m:mi><m:msub><m:mi>X</m:mi><m:mn>2</m:mn></m:msub></m:mrow></m:math>, which mediates <n:math xmlns:n="http://www.w3.org/1998/Math/MathML"><n:mi>p</n:mi></n:math>-based magnetotransport. Notably, these systems display significant anomalous, spin, and orbital Hall conductivities. We find that in <o:math xmlns:o="http://www.w3.org/1998/Math/MathML"><o:mrow><o:mi>Gd</o:mi><o:msub><o:mi>X</o:mi><o:mn>2</o:mn></o:msub></o:mrow></o:math>, the strength of correlations controls the relative position of the <p:math xmlns:p="http://www.w3.org/1998/Math/MathML"><p:mi>p</p:mi><p:mo>,</p:mo><p:mo> </p:mo><p:mi>d</p:mi></p:math>, and <q:math xmlns:q="http://www.w3.org/1998/Math/MathML"><q:mi>f</q:mi></q:math> states and their hybridization, which has a crucial impact on <r:math xmlns:r="http://www.w3.org/1998/Math/MathML"><r:mi>p</r:mi></r:math>-state polarization and the anomalous Hall effect, but not the spin and orbital Hall effects. Moreover, we find that the application of strain can significantly modify the electronic structure of the monolayers, resulting in quantized charge, spin, and orbital transport in <s:math xmlns:s="http://www.w3.org/1998/Math/MathML"><s:msub><s:mi>GdTe</s:mi><s:mn>2</s:mn></s:msub></s:math> via a strain-mediated orbital inversion mechanism taking place at the Fermi energy. Our findings suggest that rare-earth dichalcogenides hold promise as a platform for topological spintronics and orbitronics. Published by the American Physical Society 2024

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