Magnetoresistance of semi-metals: the case of antimony

TL;DR

This study reveals that elemental antimony exhibits the largest high-field magnetoresistance among semi-metals, explained by anisotropic mobility and disorder effects, with implications for understanding magnetoresistance mechanisms.

Contribution

It provides a detailed analysis of antimony's angle-dependent magnetoresistance using a semi-classical model with anisotropic mobility, highlighting the role of disorder and carrier compensation.

Findings

Antimony shows the largest high-field magnetoresistance among semi-metals.

Field-dependent mobility explains the sub-quadratic magnetoresistance.

A semi-classical model with anisotropic mobility fits the experimental data well.

Abstract

Large unsaturated magnetoresistance has been recently reported in numerous semi-metals. Many of them have a topologically non-trivial band dispersion, such as Weyl nodes or lines. Here, we show that elemental antimony displays the largest high-field magnetoresistance among all known semi-metals. We present a detailed study of the angle-dependent magnetoresistance and use a semi-classical framework invoking an anisotropic mobility tensor to fit the data. A slight deviation from perfect compensation and a modest variation with magnetic field of the components of the mobility tensor are required to attain perfect fits at arbitrary strength and orientation of magnetic field in the entire temperature window of study. Our results demonstrate that large orbital magnetoresistance is an unavoidable consequence of low carrier concentration and the sub-quadratic magnetoresistance seen in many semi-metals can be attributed to field-dependent mobility, expected whenever the disorder length-scale exceeds the Fermi wavelength.