Topological crystalline semimetals in nonsymmorphic lattices

Article

关键词: QUANTUM SPIN HALL;    PHASE-TRANSITION;    INSULATORS;    DISCOVERY;    WELLS;    METAL;   

DOI  :  10.1103/PhysRevB.93.155140

来源: SCIE

【 摘 要 】

Numerous efforts have been devoted to reveal exotic semimetallic phases with topologically nontrivial bulk and/or surface states in materials with strong spin-orbit coupling. In particular, semimetals with nodal line Fermi surface (FS) exhibit novel properties, and searching for candidate materials becomes an interesting research direction. Here we provide a generic condition for a fourfold degenerate nodal line FS in nonsymmorphic crystals with inversion and time-reversal symmetry (TRS). When there are two glide planes or screw axes perpendicular to each other, a pair of Bloch bands related by nonsymmorphic symmetry become degenerate on a Brillouin zone (BZ) boundary. There are two pairs of such bands, and they disperse in a way that the partners of two pairs are exchanged on other BZ boundaries. This enforces a nodal line FS on a BZ boundary plane protected by nonsymmorphic symmetries. When TRS is broken, fourfold degenerate Dirac points or Weyl ring FS could occur depending on a direction of the magnetic field. On a certain surface double helical surface states exist, which become double Fermi arcs as TRS is broken.

【 授权许可】

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