Manifestation of the superconducting pairing of repulsive particles with a large total momentum in Andreev reflection

Features of Andreev reflection at the normal metal–superconductor interface in the presence of repulsive-interaction-induced pairing with a large total momentum K have been analyzed. When the direction of the motion of a hole arising upon the formation of a pair with nonzero total momentum by an incident electron corresponds to transmission, the intensity of Andreev reflection decreases compared to the case K = 0. Another cause of the decrease in the intensity is that, owing to the repulsive interaction, the superconducting order parameter has a zero line, and the quasiparticle energy minimum, which determines the turning point, does not coincide with the Fermi contour on which the quasiparticle charge changes its sign (charge asymmetry).