  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.
