Superconducting 2D system with lifted spin degeneracy: mixed singlet-triplet state.
Motivated by recent experimental findings, we have developed a theory of the superconducting state for 2D metals without inversion symmetry modeling the geometry of a surface superconducting layer in a field-effect transistor or near the boundary doped by adsorbed ions. In such systems the twofold spin degeneracy is lifted by spin-orbit interaction, and singlet and triplet pairings are mixed in the wave function of the Cooper pairs. As a result, spin magnetic susceptibility becomes anisotropic and Knight shift retains finite and rather high value at T = 0.
Gor'kov
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LP
National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
Rashba
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EI