Absence of helical surface states in bulk semimetals with broken inversion symmetry

Abstract

Whereas the concept of topological band-structures was developed originally for insulators with a bulk bandgap, it has become increasingly clear that the prime consequences of a non-trivial topology -- spin-momentum locking of surface states -- can also be encountered in gapless systems. Concentrating on the paradigmatic example of mercury chalcogenides HgX (X = Te, Se, S), we show that the existence of helical semimetals, i.e. semimetals with topological surface states, critically depends on the presence of crystal inversion symmetry. An infinitesimally small broken inversion symmetry (BIS) renders the helical semimetallic state unstable. The BIS is also very important in the fully gapped regime, renormalizing the surface Dirac cones in an anisotropic manner. As a consequence the handedness of the Dirac cones can be flipped by a biaxial stress field.

7 pages, 4 figures

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Cited by in corpus (7)

• Weyl and Dirac Semimetals in Three Dimensional Solids
• Colloquium: Topological Band Theory
• Topological states in superlattices of HgTe-class materials for engineering three-dimensional flat bands
• Surface-state spin textures in strained bulk HgTe: strain-induced topological phase transitions
• Engineering axion insulator phase in superlattices with inversion symmetry breaking
• Unconventional topological phase transition from semimetal to insulator in SnBi2Te4: Role of anomalous thermal expansion
• Nonlinear planar magnetotransport as a probe of the topology of surface states