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 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.
Citation
Sun , Z , Enayat , M , Maldonado , A I , Lithgow , C , Yelland , E , Peets , D C , Yaresko , A , Schnyder , A P & Wahl , P 2015 , ' Dirac surface states and nature of superconductivity in noncentrosymmetric BiPd ' , Nature Communications , vol. 6 , 6633 . https://doi.org/10.1038/ncomms7633
Publication
Nature Communications
Status
Peer reviewed
ISSN
2041-1723Type
Journal article
Collections
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