Tunable band-filling effects on thermoelectric properties and anomalous Hall conductivity in Weyl semimetal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>Co</mml:mi> <mml:mn>3</mml:mn> </mml:msub> <mml:msub>

The magnetic Weyl semimetal <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:msub> <a:mi>Co</a:mi> <a:mn>3</a:mn> </a:msub> <a:msub> <a:mi>Sn</a:mi> <a:mn>2</a:mn> </a:msub> <a:msub> <a:mi mathvariant="normal">S</a:mi> <a:mn>2</a:mn> </a:msub> </a:mrow> </a:math> has garnered significant experimental and theoretical interest, particularly regarding its electronic structure and transport properties. In this study, we comprehensively investigated the effects of Fe and Ni substitution in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mrow> <c:msub> <c:mi>Co</c:mi> <c:mn>3</c:mn> </c:msub> <c:msub> <c:mi>Sn</c:mi> <c:mn>2</c:mn> </c:msub> <c:msub> <c:mi mathvariant="normal">S</c:mi> <c:mn>2</c:mn> </c:msub> </c:mrow> </c:math> . The temperature-dependent Seebeck coefficient ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:mrow> <e:mi>S</e:mi> </e:mrow> </e:math> ) implies that the reduction of the band gap and the shift in the Fermi level ( <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"> <f:msub> <f:mi>E</f:mi> <f:mi mathvariant="normal">F</f:mi> </f:msub> </f:math> ) due to Fe and Ni substitution, which was supported by angle-resolved photoemission spectroscopy results. These band-structure modifications influence not only thermoelectric (TE) performance but also the anomalous Hall conductivity ( <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"> <h:msubsup> <h:mi>σ</h:mi> <h:mrow> <h:mi>xy</h:mi> </h:mrow> <h:mi mathvariant="normal">A</h:mi> </h:msubsup> </h:math> ). Specifically, Fe substitution increases <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"> <j:msubsup> <j:mi>σ</j:mi> <j:mrow> <j:mi>xy</j:mi> </j:mrow> <j:mi mathvariant="normal">A</j:mi> </j:msubsup> </j:math> via skew scattering, while Ni substitution increases <l:math xmlns:l="http://www.w3.org/1998/Math/MathML"> <l:msubsup> <l:mi>σ</l:mi> <l:mrow> <l:mi>xy</l:mi> </l:mrow> <l:mi mathvariant="normal">A</l:mi> </l:msubsup> </l:math> via intrinsic deflection with minor skew scattering. Additionally, the Fe and Ni dopant-induced changes in the <n:math xmlns:n="http://www.w3.org/1998/Math/MathML"> <n:mrow> <n:mi>c</n:mi> <n:mo>/</n:mo> <n:mi>a</n:mi> </n:mrow> </n:math> ratio were demonstrated using high-resolution powder synchrotron x-ray diffraction, which explains the different modulation in the magnetic anisotropy of <o:math xmlns:o="http://www.w3.org/1998/Math/MathML"> <o:mrow> <o:msub> <o:mi>Co</o:mi> <o:mn>3</o:mn> </o:msub> <o:msub> <o:mi>Sn</o:mi> <o:mn>2</o:mn> </o:msub> <o:msub> <o:mi mathvariant="normal">S</o:mi> <o:mn>2</o:mn> </o:msub> </o:mrow> </o:math> due to the magnetostriction effect. Notably, the oxidation states of Co, Fe, and Ni in each single crystal were confirmed as 0 using x-ray absorption near-edge structure analysis, further explaining the dopant-induced suppression in ferromagnetism of <q:math xmlns:q="http://www.w3.org/1998/Math/MathML"> <q:mrow> <q:msub> <q:mi>Co</q:mi> <q:mn>3</q:mn> </q:msub> <q:msub> <q:mi>Sn</q:mi> <q:mn>2</q:mn> </q:msub> <q:msub> <q:mi mathvariant="normal">S</q:mi> <q:mn>2</q:mn> </q:msub> </q:mrow> </q:math> . These findings provide deeper insight into the band-filling effects on both TE and anomalous Hall transport in <s:math xmlns:s="http://www.w3.org/1998/Math/MathML"> <s:mrow> <s:msub> <s:mi>Co</s:mi> <s:mn>3</s:mn> </s:msub> <s:msub> <s:mi>Sn</s:mi> <s:mn>2</s:mn> </s:msub> <s:msub> <s:mi mathvariant="normal">S</s:mi> <s:mn>2</s:mn> </s:msub> </s:mrow> </s:math> , offering perspectives for topological spintronics and TE applications.