Semimetal-Metal Transition and Quantum Electronic Transport in Ultrathin WTe$_{\mathrm{2}}$

We report low-temperature electronic transport measurements of ultrathin WTe$_{\mathrm{2}}$. By encapsulating samples inside a glove-box, we can approach the intrinsic electronic transport physics of the system. We find that tri-layer samples remain semimetallic, similar to bulk crystals. We tune the system from an intrinsic semimetallic state into a simple metallic state by doping via an electrostatic gate, which results in total suppression of magnetoresistance and disappearance of the hole pocket in Shubnikov-de Haas oscillations. However, the magnetoresistance of semimetallic 2D WTe$_{\mathrm{2}}$ follows a distinctly sub-quadratic power law, in contrast to bulk crystals which show nearly quadratic behavior, suggesting new physics in the 2D limit. Finally, we report on our progress towards electronic transport in the monolayer limit.