Magnetotransport properties of the triply degenerate node topological semimetal tungsten carbide

摘要

We report the magnetoresistance (MR), Hall effect, and de Haas–van Alphen (dHvA) effect studies of single crystals of tungsten carbide, WC, which is predicted to be a new type of topological semimetal with triply degenerate nodes. With the magnetic field rotated in the plane perpendicular to the current, WC shows a field induced metal-to-insulator-like transition and large nonsaturating quadratic MR at low temperatures. As the magnetic field parallel to the current, a pronounced negative longitudinal MR only can be observed for a certain direction of current flow. The Hall effect indicates WC is a perfect compensated semimetal, which may be related to the large nonsaturating quadratic MR. The analysis of dHvA oscillations reveals thatWC is a multiband system with small cross-sectional areas of Fermi surface and light cyclotron effective masses. Our results indicate that WC is an ideal platform to study the recently proposed “new fermions” with triply degenerate crossing points.