  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.
