Coexistence of Different Symmetry Order Parameters near a Surface ind-Wave Superconductors III

Abstract

In previous papers a possibility of coexistence of different symmetry order parameters and their physical properties have been studied for the (1, 1, 0) surface of d x 2 - y 2 -wave superconductors. The present report extends them to discuss the dependence on the direction of the surface, determining the order parameters self-consistently. For simplicity the surface is assumed to be specular. In the case of a general direction of the surface the symmetry is lower than that for the (1, 1, 0) surface. As a consequence, d x 2 - y 2 mixes with other symmetry order parameters at the surface. The relative phase between the coexisting order parameters depends on the surface direction; physical properties also change accordingly. Due to the nature of admixture the appearance of the secondary order parameter(s) is possible, even when their couplings are repulsive.