Large linear magnetoresistance caused by disorder in WTe2- δthin film

Abstract

Weyl semimetal WTe₂has attracted considerable attention owing to its extremely large, unsaturated and quadratic magnetoresistance. Here, we study the magnetotransport properties of WTe_2-δthin film, which shows an unsaturated and linear magnetoresistance of up to ∼1650%. A more complex and accurate method, known as the maximum entropy mobility spectrum, is used to analyze the mobility and density of carriers. The results show that linear magnetoresistance can be explained by the classical disorder model because the slope of linear magnetoresistance and the crossover field are proportional to the mobility and inverse mobility, respectively. Furthermore, the validity of the maximum entropy mobility spectrum is validated by the Shubnikov-de Haas oscillations. Moreover, at low temperature, we determined that the unsaturated and near-quadratic magnetoresistance in the WTe_1.93thin film can be explained by charge compensation. Note that the electron-hole compensation is broken in the WTe_1.42thin film, which indicates that the carrier scattering induced by the disorder may suppress the charge compensation in the WTe₂sample with defects/dopants. To summarize, the discovery of disorder-induced linear magnetoresistance allows us to explain different magnetoresistance behaviors of WTe₂.

Keywords: WTe2−δ; Weyl semimetal; different magnetoresistance behaviors; disorder; linear magnetoresistance.