Observation of Zeeman splitting in the spin-polarized chiral fermion state in the Weyl semimetal TaAs
Phys. Rev. B 112, 045117 – Published 10 July, 2025
DOI: https://doi.org/10.1103/qjt5-x6p4
Abstract
We report a spin-polarized chiral fermion state in the prototypical Weyl semimetal TaAs through a combination of Shubnikov-de Haas (SdH) oscillation measurements and Density functional theory (DFT) calculations. Our first-principles calculations reveal that the Fermi pockets surrounding neighboring Weyl nodes are strongly spin-polarized with opposite chiralities, arising from the interplay between spin-orbit coupling, spatial inversion asymmetry, and the crystalline mirror symmetries of the TaAs lattice. When subjected to an external magnetic field, they are observed to undergo a distinct Zeeman splitting, appearing as pronounced SdH oscillations, whose amplitude and frequencies can significantly vary depending on the direction of the magnetic field in the mirror planes protecting the chiralities of the Weyl nodes.
