Non-saturating large magnetoresistance in semimetals

TL;DR

This study investigates the magnetoresistance mechanisms in four non-magnetic topological semimetals, showing how combined magnetotransport and susceptibility measurements can distinguish different origins of large, non-saturating MR.

Contribution

It provides empirical criteria using susceptibility and Hall angle data to differentiate between MR arising from guiding center motion and charge compensation in topological semimetals.

Findings

NbP and TaP exhibit non-saturating MR due to guiding center motion.

NbSb2 and TaSb2 show MR from nearly perfect charge compensation.

Magnetotransport and susceptibility measurements can categorize MR origins.

Abstract

The rapidly expanding class of quantum materials known as {\emph{topological semimetals}} (TSM) display unique transport properties, including a striking dependence of resistivity on applied magnetic field, that are of great interest for both scientific and technological reasons. However, experimental signatures that can identify or discern the dominant mechanism and connect to available theories are scarce. Here we present the magnetic susceptibility ($\chi$), the tangent of the Hall angle ($\tan\theta_H$) along with magnetoresistance in four different non-magnetic semimetals with high mobilities, NbP, TaP, NbSb$_2$ and TaSb$_2$, all of which exhibit non-saturating large MR. We find that the distinctly different temperature dependences, $\chi(T)$ and the values of $\tan\theta_H$ in phosphides and antimonates serve as empirical criteria to sort the MR from different origins: NbP and TaP being uncompensated semimetals with linear dispersion, in which the non-saturating magnetoresistance arises due to guiding center motion, while NbSb$_2$ and TaSb$_2$ being {\it compensated} semimetals, with a magnetoresistance emerging from nearly perfect charge compensation of two quadratic bands. Our results illustrate how a combination of magnetotransport and susceptibility measurements may be used to categorize the increasingly ubiquitous non-saturating large magnetoresistance in TSMs.