Direct evidence for charge compensation induced large magnetoresistance in thin WTe2

TL;DR

This study provides direct evidence that charge compensation is the main cause of large, non-saturating magnetoresistance in thin WTe2, achieved through electrostatic doping and in-situ transport measurements.

Contribution

It explicitly demonstrates charge compensation as the key mechanism for large MR in WTe2 using electrostatic tuning and magneto-transport analysis.

Findings

Maximum MR of 10600% at charge balance point.

Non-monotonic gate dependence of MR observed.

Temperature-dependent MR correlates with carrier mobility.

Abstract

Since the discovery of extremely large non-saturating magnetoresistance (MR) in WTe2, much effort has been devoted to understanding the underlying mechanism, which is still under debate. Here, we explicitly identify the dominant physical origin of the large non-saturating MR through in-situ tuning of the magneto-transport properties in thin WTe2 film. With an electrostatic doping approach, we observed a non-monotonic gate dependence of the MR. The MR reaches a maximum (10600%) in thin WTe2 film at certain gate voltage where electron and hole concentrations are balanced, indicating that the charge compensation is the dominant mechanism of the observed large MR. Besides, we show that the temperature dependent magnetoresistance exhibits similar tendency with the carrier mobility when the charge compensation is retained, revealing that distinct scattering mechanisms may be at play for the temperature dependence of magneto-transport properties. Our work would be helpful for understanding mechanism of the large MR in other nonmagnetic materials and offers an avenue for achieving large MR in the non-magnetic materials with electron-hole pockets.