In a superconductor that lacks inversion symmetry, the spatial part of the Cooper pair wave function has a reduced symmetry, allowing for the mixing of spin-singlet and spin-triplet Cooper pairing channels and thus providing a pathway to a non-trivial superconducting state. Materials with a non-centrosymmetric crystal structure and with strong spin-orbit coupling are a platform to realize these possibilities. Here, we report the synthesis and characterisation of high quality crystals of Sn4As3, with non-centrosymmetric unit cell (R3m). We have characterised the normal and superconducting state using a range of methods. Angle-resolved photoemission spectroscopy shows a multiband Fermi surface and the presence of two surface states, confirmed by Density-functional theory calculations. Specific heat measurements reveal a superconducting critical temperature of Tc∼1.14 K and an upper critical magnetic field of Hc≳7 mT, which are both confirmed by ultra-low temperature scanning tunneling microscopy and spectroscopy. Scanning tunneling spectroscopy shows a fully formed superconducting gap, consistent with conventional s-wave superconductivity.
|Journal||arXiv.org e-Print archive|
|Publication status||Submitted - Dec 2019|
Marques, C. A., Neat, M. J., Yim, C. M., Watson, M. D., Heil, C., Pervakov, K. S., ... Wahl, P. (2019). Electronic structure and superconductivity of the non-centrosymmetric Sn4As3. Manuscript submitted for publication.