Perfect charge compensation in WTe2 for the extraordinary magnetoresistance: From bulk to monolayer

TL;DR

This study uses first principles calculations to show that WTe2 bulk and monolayer both exhibit perfect charge compensation and high mobility, leading to extraordinary magnetoresistance with potential applications in nanostructured magnetic devices.

Contribution

It demonstrates that monolayer WTe2 maintains the charge compensation and high mobility of bulk, predicting similar extraordinary magnetoresistance effects at the monolayer level.

Findings

WTe2 bulk exhibits perfect electron-hole charge compensation.

Monolayer WTe2 retains semimetallic properties with equal carrier concentrations.

High carrier mobilities are present in WTe2 monolayer, suggesting similar MR effects as bulk.

Abstract

The electronic structure of WTe2 bulk and layers are investigated by using the first principles calculations. The perfect electron-hole (n-p) charge compensation and high carrier mobilities are found in WTe2 bulk, which may result in the large and non-saturating magnetoresistance (MR) observed very recently in the experiment [Ali et al., Nature 514, 205 (2014)]. The monolayer and bilayer of WTe2 preserve the semimetallic property, with the equal hole and electron carrier concentrations. Moreover, the very high carrier mobilities are also found in WTe2 monolayer, indicating that the WTe2 monolayer would have the same extraordinary MR effect as the bulk, which could have promising applications in nanostructured magnetic devices.