Gate Tunable Magneto-resistance of Ultra-Thin WTe2 Devices

摘要

In this work, the magneto-resistance (MR) of ultra-thin WTe2/BNheterostructures far away from electron-hole equilibrium is measured. Thechange of MR of such devices is found to be determined largely by a singletunable parameter, i.e. the amount of imbalance between electrons and holes. Wealso found that the magnetoresistive behavior of ultra-thin WTe2 devices iswell-captured by a two-fluid model. According to the model, the change of MRcould be as large as 400,000%, the largest potential change of MR among allmaterials known, if the ultra-thin samples are tuned to neutrality whenpreserving the mobility of 167,000 cm2V-1s-1 observed in bulk samples. Ourfindings show the prospects of ultra-thin WTe2 as a variable magnetoresistancematerial in future applications such as magnetic field sensors, informationstorage and extraction devices, and galvanic isolators. The results alsoprovide important insight into the electronic structure and the origin of thelarge MR in ultra-thin WTe2 samples.