Anomalous Hall effect in the antiferromagnetic Weyl semimetal SmAlSi

TL;DR

This paper reports the observation of the anomalous Hall effect in the antiferromagnetic and paramagnetic states of the non-centrosymmetric Weyl semimetal SmAlSi, introducing a new mechanism based on magnetic field-induced Weyl node evolution.

Contribution

It demonstrates the presence of AHE in non-centrosymmetric Weyl semimetals without ferromagnetism and proposes a novel mechanism involving Weyl node evolution under magnetic fields.

Findings

AHE observed in both AFM and PM states of SmAlSi.

Angle-dependent quantum oscillations confirm Weyl points.

Unconventional power law temperature dependence of AHC.

Abstract

The intrinsic anomalous Hall effect (AHE) has been reported in numerous ferromagnetic (FM) Weyl semimetals. However, AHE in the antiferromagnetic (AFM) or paramagnetic (PM) state of Weyl semimetals has been rarely observed experimentally, and only in centrosymmetric materials. Different mechanisms have been proposed to establish the connection between the AHE and the type of magnetic order. In this paper, we report AHE in both the AFM and PM states of non-centrosymmetric compound SmAlSi. To account for the AHE in non-centrosymmetric Weyl semimetals without FM, we introduce a new mechanism based on magnetic field-induced Weyl nodes evolution. Angle-dependent quantum oscillations in SmAlSi provide evidence for the Weyl points and large AHE in both the PM and the AFM states. The proposed mechanism qualitatively explains the temperature dependence of the anomalous Hall conductivity (AHC), which displays unconventional power law behavior of the AHC in both AFM and PM states of SmAlSi.