Dichotomy of magnetic effect between Weyl fermions and anomalous Hall effect in PrAlSi

Abstract Three key aspects of magnetic topological materials, i.e ., band topology, magnetic order and anomalous transport are closed related with each other, laying the ground for exotic phenomena such as topological magnetoelectric and magneto-optical effects. Here in the ferromagnetic Weyl semimetal PrAlSi, we report negligible effect of magnetic order on the band structure featuring Weyl fermions, as directly observed by angle-resolved photoemission spectroscopy. Instead, both anomalous and normal Hall effects show clear temperature/magnetism dependence. While the longitudinal conductivity ( $${{{\boldsymbol{\sigma }}}}_{{{\boldsymbol{xx}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>xx</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) is deep in the empirically intrinsic region, the anomalous Hall conductivity ( $${{{\boldsymbol{\sigma }}}}_{{{\boldsymbol{AHE}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>AHE</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) is quadratically proportional to $${{{\boldsymbol{\sigma }}}}_{{{\boldsymbol{xx}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>xx</mml:mi> </mml:mrow> </mml:msub> </mml:math> , suggesting giant anomalous Hall angle at moderate $${{{\boldsymbol{\sigma }}}}_{{{\boldsymbol{xx}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>xx</mml:mi> </mml:mrow> </mml:msub> </mml:math> . Our findings point to disentangled band topology and anomalous transport, as well as the possibility to achieve high $${{{\boldsymbol{\sigma }}}}_{{{\boldsymbol{AHE}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>AHE</mml:mi> </mml:mrow> </mml:msub> </mml:math> in highly conductive, ultrathin PrAlSi, suitable for anomalous Hall sensors and spin-transfer torque application.