Electronic structure and superconductivity of the non-centrosymmetric Sn4As3

Carolina A. Marques, M. J. Neat, Chi M. Yim, M. D. Watson, Christoph Heil, K. S. Pervakov, V. A. Vlasenko, V. M. Pudalov, A. V. Muratov, T. K. Kim, Peter Wahl

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Abstract

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.
Original languageEnglish
Article number1912.06625
JournalarXiv.org e-Print archive
Volume1912
Issue number06625
Publication statusSubmitted - Dec 2019

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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.