Dirac Surface States and Nature of Superconductivity in Noncentrosymmetric BiPd

Abstract

In non-magnetic bulk materials, inversion symmetry protects the spin degeneracy. If the bulk crystal structure lacks a centre of inversion, however, spin-orbit interactions lift the spin degeneracy, leading to a Rashba metal whose Fermi surfaces exhibit an intricate spin texture. In superconducting Rashba metals a pairing wavefunction constructed from these complex spin structures will generally contain both singlet and triplet character. Here we examine the possible triplet components of the order parameter in noncentrosymmetric BiPd, combining for the first time in a noncentrosymmetric superconductor macroscopic characterization, atomic-scale ultra-low-temperature scanning tunnelling spectroscopy, and relativistic first-principles calculations. While the superconducting state of BiPd appears topologically trivial, consistent with Bardeen-Cooper-Schrieffer theory with an order parameter governed by a single isotropic s-wave gap, we show that the material exhibits Dirac-cone surface states with a helical spin polarization.

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References in corpus (8)

• Classification of topological insulators and superconductors in three spatial dimensions
• Topological Phases of Noncentrosymmetric Superconductors: Edge States, Majorana Fermions, and the Non-Abelian Statistics
• Anomalous Andreev bound state in non-centrosymmetric superconductors
• Majorana Fermions in Nodal Superconductors: Gapless Topological Phase
• Surface bound states and spin currents in non-centrosymmetric superconductors
• Andreev bound states and tunneling characteristics of a non-centrosymmetric superconductor
• Gap structure in noncentrosymmetric superconductors
• Observation of Andreev bound state and multiple energy gaps in the non-centrosymmetric superconductor BiPd

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