Thickness dependent magneto transport properties of WTe2 thin films

Abstract

We report the systemic magneto transport studies on a-few-layers exfoliated WTe2 thin film devices. The non-saturating and large magnetoresistance (MR), proportional to B2, are observed in all devices. Hall effect modeling using the classical two-band model indicate the nearly identical electron and hole densities in thicker devices while unequal densities of electrons and holes in thinner devices at low temperatures. As a result, we attribute the large non-saturating MR at low temperatures in thicker devices to balanced electron and hole density while in thinner devices to low mobility caused by surface contamination and degradation. Our results suggest both carrier densities and mobility play significant roles in determining the magnitude and the non-saturating behavior of MR.