Observation of Dirac surface states in the noncentrosymmetric superconductor BiPd

Abstract

Materials with strong spin-orbit coupling (SOC) have in recent years become a subject of intense research due to their potential applications in spintronics and quantum information technology. In particular, in systems which break inversion symmetry, SOC facilitates the Rashba-Dresselhaus effect, leading to a lifting of spin degeneracy in the bulk and intricate spin textures of the Bloch wave functions. Here, by combining angular resolved photoemission (ARPES) and low temperature scanning tunneling microscopy (STM) measurements with relativistic first-principles band structure calculations, we examine the role of SOC in single crystals of noncentrosymmetric BiPd. We report the detection of several Dirac surface states, one of which exhibits an extremely large spin splitting. Unlike the surface states in inversion-symmetric systems, the Dirac surface states of BiPd have completely different properties at opposite faces of the crystal and are not trivially linked by symmetry. The spin-splitting of the surface states exhibits a strong anisotropy by itself, which can be linked to the low in-plane symmetry of the surface termination.

6 page letter, + supplementary material

References in corpus (11)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Classification of topological insulators and superconductors in three spatial dimensions
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• Topological Phases of Noncentrosymmetric Superconductors: Edge States, Majorana Fermions, and the Non-Abelian Statistics
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• Transmission of topological surface states through surface barriers
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• Dirac Surface States and Nature of Superconductivity in Noncentrosymmetric BiPd
• Metallic surface electronic state in half-Heusler compounds RPtBi (R = Lu, Dy, Gd)
• Observation of Andreev bound state and multiple energy gaps in the non-centrosymmetric superconductor BiPd

Cited by in corpus (6)

• Evidence of topological nodal lines and surface states in the centrosymmetric superconductor SnTaS2
• Exceptional Dirac states in a non-centrosymmetric superconductor, BiPd
• Low-temperature thermal expansion of the topological material candidates $\beta$-PtBi${}_2$ and $\beta$-Bi${}_2$Pd
• Fermi surface and band structure of BiPd from ARPES studies
• Temperature dependence of the lower critical field of the noncentrosymmetric superconductor $\alpha$-BiPd
• Conventional superconductivity in single-crystalline BiPt