Transport Properties of Topological Semimetal Tungsten Carbide in the 2D Limit

Abstract

AbstractRecent theoretical calculations and spectroscopy measurements have shown that several materials with the tungsten carbide‐type structure, such as molybdenum phosphide and tungsten carbide (WC), are a new type of topological semimetal hosting triply degenerate nodal points. So far, most of experimental studies are performed on large‐size bulk crystal. 2D nanostructures, with large surface‐to‐volume ratio, are expected to provide an attractive system for probing topological surface states and the development of device applications. Here the transport characterization of high‐quality ultrathin WC single crystals is reported. The magnetoresistance (MR) shows a strong anisotropic behavior, which may be attributed to the transport anomalies of three‐component fermions as theoretically proposed. The scaling analysis reveals the presence of the surface states in WC. The observation of the nonsaturating MR in strong magnetic fields, together with nonlinear and strong temperature dependent Hall effect, is consistent with the proposed multiple bands character of carriers in WC. In addition, a low‐temperature upturn in the resistance is observed, indicating that electron–electron interaction plays a prominent role in charge transport. The results demonstrate that the ultrathin WC crystals offer a potential platform for exploring exotic transport properties arising from the three‐component fermions in the 2D limit.