Pseudo-gap in tunneling spectra as a signature of inhomogeneous superconductivity in oxide interfaces

摘要: We present a theory for the pseudo-gap state recently observed at LaAlO3/SrTiO3 interface, based on superconducting islands embedded in metallic background. Superconductivity within each island is BCS-like, and local critical temperatures are randomly distributed, some of them necessarily exceeding temperature global percolation to zero resistance state. Consequently, tunneling spectra display suppression density states coherence peaks already well above percolative transition. This model inhomogeneous superconductivity accounts experimental spectra. The dependence suggests that sizable fraction background becomes by proximity effect when lowered.