Zeros of the order parameter of d_{x^2-y^2} superconducting film in the presence of uniform current

Abstract

We show that additional p-wave component is generated in the pure d-wave superconductor in the presence of the uniform current. When the current flows in the antinodal direction the spectrum has a gap over all Fermi surface. If the current flows in the nodal direction, the gap opens only in the direction parallel to the current. The correction to the current due to the p-wave component of the order parameter is linear in vector potential. We show, that the spin-orbit coupling may be responsible for the additional component of the order parameter.