Magnetoresistance and robust resistivity plateau in MoAs2

TL;DR

This study reports on the growth and detailed transport properties of MoAs2 single crystals, revealing a robust resistivity plateau, large magnetoresistance, and possible Lifshitz transition, indicating complex metallic and topological behaviors.

Contribution

First detailed transport study of MoAs2 revealing a Lifshitz transition and large magnetoresistance in a centrosymmetric transition-metal dipnictide.

Findings

Resistivity plateau persists up to 9 T magnetic field.

Large positive MR of about 2600% at 2 K and 9 T.

Evidence of a Lifshitz transition between 30 K and 60 K.

Abstract

We have grown the MoAs$_2$ single crystal which crystallizes in a monoclinic structure with C2/m space group. Transport measurements show that MoAs$_2$ displays a metallic behavior at zero field and undergoes a metal-to-semiconductor crossover at low temperatures when the applied magnetic field is over 5 T. A robust resistivity plateau appears below 18 K and persists for the field up to 9 T. A large positive magnetoresistance (MR), reaching about 2600\% at 2 K and 9 T, is observed when the field is perpendicular to the current.The MR becomes negative below 40 K when the field is rotated to be parallel to the current. The Hall resistivity shows the non-linear field-dependence below 70 K. The analysis using two-band model indicates a compensated electron-hole carrier density at low temperatures. A combination of the breakdown of Kohler's rule, the abnormal drop and the cross point in Hall data implies that a possible Lifshitz transition has occurred between 30 K and 60 K, likely driving the compensated electron-hole density, the large MR as well as the metal-semiconductor transition in MoAs$_2$. Our results indicate that the family of centrosymmetric transition-metal dipnictides has rich transport behavior which can in general exhibit variable metallic and topological features.