Split fermi surface properties of VSi₂ without mirror planes in the chiral crystal structure

VSi₂ is hexagonal in the crystal structure, and the basal plane stacks along the [0001] direction. Interestingly, each plane is rotated by 60° relative to the neighboring one. Therefore, there exist no mirror planes in this chiral structure. We carried out a de Haas-van Alphen (dHvA) experiment and clarified the Fermi surface properties. Each dHvA branch was found to be split into two branches on the basis of the antisymmetric spin-orbit interaction. The magnitude of the antisymmetric spin-orbit interaction in this chiral structure was determined for the first time to be 19 K for dHvA branch α (dHvA frequency F - 7:9 × 10⁷ Oe and cyclotron mass m _c^* = 1:6 m₀), 39 K for branch β (F = 4:1 × 10⁷Oe and m_c^* = 3:4 m ₀), and 110K for branch γ(F=1:8×10⁷Oe and m _c^* = 23 m₀). These dHvA branches correspond to the main Fermi surfaces, which are well explained by the results of the energy band calculations based on the full potential linear augmented plane wave (FLAPW) method. The present values are mainly due to the V-3d conduction electrons.