1304.0631 (G. Tkachov)

Suppression of surface p-wave superconductivity in disordered
topological insulators    [PDF]

G. Tkachov

The paper proposes a self-consistent Green's function description of the induced surface superconductivity in a disordered three-dimensional topological insulator (TI) coupled to an s-wave superconductor. We recover earlier results regarding the induced spin-triplet p-wave pairing, showing that a mixture of p- and s-wave pair correlations appears as a result of broken spin-rotation symmetry on the helical surface of the TI. Unlike the s-wave pairing, the p-wave component is found to be suppressed in dirty TIs in which the elastic mean-free path is much smaller than the superconducting coherence length. The suppression is due to the generic nonlocality of the spin-triplet correlations, which makes them strongly dependent on the mean-free path in a disordered system. In dirty TIs the induced superconductivity is predicted to be predominantly s-wave like. In cleaner systems, however, the p-wave component may reach a magnitude comparable with the s-wave pairing.

View original: http://arxiv.org/abs/1304.0631