In-gap states in superconducting LaAlO3-SrTiO3 interfaces observed by tunneling spectroscopy

Article

关键词: ANDREEV BOUND-STATES;    MAJORANA FERMIONS;    LAALO3/SRTIO3 INTERFACE;    MAGNETIC-IMPURITIES;    UNCONVENTIONAL SUPERCONDUCTORS;    TOPOLOGICAL SUPERCONDUCTIVITY;    CUPRATE SUPERCONDUCTORS;    OXIDE INTERFACES;    EXCHANGE MODEL;    SURFACE-STATES;   

DOI  :  10.1103/PhysRevB.96.014513

来源: SCIE

【 摘 要 】

We identified quasiparticle states at well-defined energies inside the superconducting gap of the electron system at the LaAlO3-SrTiO3 interface using tunneling spectroscopy. The states are found only in a number of samples and depend upon the thermal-cycling history of the samples. The states consist of a peak at zero energy and other peaks at finite energies, symmetrically placed around zero energy. These peaks disappear, together with the superconducting gap, with increasing temperature and magnetic field. We discuss the likelihood of various physical mechanisms that are known to cause in-gap states in superconductors and conclude that none of these mechanisms can easily explain the results. The conceivable scenarios are the formation of Majorana bound states, Andreev bound states, or the presence of an odd-frequency spin triplet component in the superconducting order parameter.

【 授权许可】

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