Planar Hall effect with sixfold oscillations in a Dirac antiperovskite

Abstract

The planar Hall effect (PHE), wherein a rotating magnetic field in the plane of a sample induces oscillating transverse voltage, has recently garnered attention in a wide range of topological metals and insulators. The observed twofold oscillations in $\ddot{I}{}_{yx}$ as the magnetic field completes one rotation are the result of chiral, orbital and/or spin effects. The antiperovskites $A_{3}B$O ($A$ = Ca, Sr, Ba; $B$ = Sn, Pb) are topological crystalline insulators whose low-energy excitations are described by a generalized Dirac equation for fermions with total angular momentum $J=3/2$. We report unusual sixfold oscillations in the PHE of Sr${}_3$SnO, which persisted nearly up to room temperature. Multiple harmonics (twofold, fourfold and sixfold), which exhibited distinct field and temperature dependencies, were detected in $\ddot{I}{}_{xx}$ and $\ddot{I}{}_{yx}$. These observations are more diverse than those in other Dirac and Weyl semimetals and point to a richer interplay of microscopic processes underlying the PHE in the antiperovskites.

9 pages, 6 figures