2020/05/29 by I. A. Nechaev, E. E. Krasovskii · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.other
paper · pdf · doi:10.1103/physrevb.102.115437
published as Phys. Rev. B 102, 115437 (2020) · 8 pages, 3 figures, 2 tables
arxiv created 2020/05/29 · arxiv updated 2020/10/02
Based on ab initio relativistic \mathbf k⋅\mathbf p theory, we derive an effective two-band model for surface states of three-dimensional topological insulators up to seventh order in k. It provides a comprehensive description of the surface spin structure characterized by a non-orthogonality between momentum and spin. We show that the oscillation of the non-orthogonality with the polar angle of k with a π/3 periodicity can be seen as due to effective six-fold symmetric spin-orbit magnetic fields with a quintuple and septuple winding of the field vectors per single rotation of k. Owing to the dominant effect of the classical Rashba field, there remains a single-winding helical spin structure but with a periodic few-degree deviation from the orthogonal locking between momentum and spin.