Electronic structure and Fermi surfaces of WTe₂ Weyl semimetal with strong electron correlations

Quantum material WTe₂ is a nearly compensated type-II Weyl semimetal which we investigate using first-principles theoretical calculations taking into account strong electron correlations. The electronic structure is calculated within DFT+U+SOC method, the value of parameter U for W-5d states is resolved from perturbation theory, we calculated it to be 3 eV for the orthorhombic T_d-WTe₂ structure. In the band structure, we identify two small hole pockets and two larger almost degenerate electron pockets along the Г-X high-symmetry direction. The valence band consists of the W-5d and Te-5p electronic states and the conduction band mostly contains W-5d states. In the band structure we also find two pairs of Weyl nodes and calculate their coordinates in momentum space, both of which lay in k_z=0 plane of the Brillouin zone. We also model Fermi surfaces and calculate their maximal cross-section area from DFT+U with the calculated and larger values of U. In the Brillouin zone there are two electron and two closed hole surfaces that correspond to small pockets in the band structure of the compound. There is also an even smaller ellipsoid-like surface around high-symmetry point Г which is very sensitive to the value of U in the calculation. These Fermi surfaces were compared with experimental measurements of Shubnikov-de-Haas oscillations and were found in good agreement with each other. From the quantum oscillations, we also observe non-trivial Berry phase and combined with our theoretical studies we conclude that Weyl points are located inside hole pockets [1]. This research was supported by Russian Science Foundation within project No. 24-72-00168.

1. B.M. Fominykh, A.N. Perevalova, S.T. Baidak, A.V. Lukoyanov, S.V. Naumov, E.B. Marchenkova, V.V. Marchenkov, J. Alloys Compd. 1039, 182966 (2025).