Investigation on high-order planar Hall effect in trigonal PtBi$_2$

TL;DR

This study systematically investigates high-order planar Hall effect and anisotropic magnetoresistance in trigonal PtBi$_2$, revealing their common physical origin related to Fermi surface anisotropy and magnetoresistance scaling.

Contribution

It provides a comprehensive analysis of high-order PHE and AMR in t-PtBi$_2$, including experimental measurements, critical conditions, and computational simulations, advancing understanding of their origins.

Findings

High-order PHE and AMR appear at low temperatures and strong magnetic fields.

High-order features are linked to Fermi surface anisotropy and magnetoresistance scaling.

Experimental results align with simulations, confirming the proposed physical mechanisms.

Abstract

The trigonal PtBi$_2$ (t-PtBi$_2$) as a Weyl semimetal possessing triply degenerate points in its electronic bands near the Fermi level endows it with rich electronic properties. Previous studies have already measured the planar Hall effect (PHE) and in-plane anisotropic magnetoresistance (AMR) of t-PtBi$_2$. We noticed that their experimental results exhibited high-order features in both the PHE and AMR, yet these features were not systematically investigated. In our work, we conducted more systematic measurements and analyses of the PHE and AMR in t-PtBi$_2$. Both PHE and AMR show high-order features under low temperatures and strong magnetic fields, and these features share a similar temperature and magnetic field dependence with the turn-on behavior of resistance and temperature curves, indicating a common physical origin for them. We further summarize the critical conditions for the emergence of high-order PHE in t-PtBi$_2$, which will help to understand the origin of high-order features. In addition, we performed computational simulations on the AMR of t-PtBi$_2$, and the results were consistent with the experiments, indicating the high-order features are the result of the combined contribution of the Fermi surface anisotropy and the scaling behavior of magnetoresistance. Our findings will contribute to a deeper understanding of the origins of high-order features in non-magnetic topological materials.