Role of spin-orbit coupling and evolution of the electronic structure of WTe2 under an external magnetic field

Here, we present a study on the temperature and angular dependence of the Shubnikov-de Haas (SdH) effect in the semimetal WTe₂. This compound has been shown to display a large, nonsaturating magnetoresistance which was attributed to nearly perfectly compensated densities of electrons and holes. We observe four fundamental SdH frequencies and attribute them to spin-orbit split, electron-like, and hole-like Fermi-surface (FS) cross-sectional areas. Their angular dependence is consistent with ellipsoidal FSs that suggest a modest excess in the density of electrons with respect to that of the holes. We show that DFT calculations fail to correctly describe the FSs of WTe₂ and find evidence for field-dependent FS cross-sectional areas. We also observe a pronounced field-induced renormalization of the effective masses. Our observations suggest that the electronic structure of WTe₂ evolves with the magnetic field due to the Zeeman splitting. This evolution is likely to contribute to its pronounced magnetoresistivity.

The work was supported by NSF through Grant No. NSFDMR-1157490, the state of Florida, DOE-BES through award No. DE-SC0002613 and by the Army Research Office through MURI Grant No. W911NF-11-10362.