Spontaneous edge current in higher chirality superconductors

The effects of finite temperature, Meissner screening, and surface roughness on the spontaneous edge current for higher chirality quasi-two-dimensional superconductors are studied in the continuum limit using the quasiclassical Eilenberger equations. We find that the total spontaneous current is nonzero at finite temperature T and maximized near T=Tc/2, where Tc is the transition temperature, although it vanishes at T=0. In the presence of surface roughness, we observe a surface current inversion in the chiral d-wave case that can be understood in terms of a disorder-induced s-wave pairing component in the rough surface regime. This conclusion is supported by a Ginzburg-Landau analysis. However, this current inversion is nonuniversal beyond the continuum limit, as demonstrated by self-consistent lattice Bogoliubov-de Gennes calculations.