Supercurrent of a quasi-one-dimensional anisotropic superconductor

By solving the Andreev equations which approximate the Bogliubov-de Gennes equations in the WKBJ approximation, we calculate the supercurrent through a quasi-one-dimensional wire artificially fabricated with d_x²-y²-wave superconductors. It is found that the supercurrent increases stepwise as a function of the Fermi energy. More interestingly, the critical current for each channel depends strongly upon the angle between the axis along which the wire lies and the crystalline axis of the superconductor, which may help us determine the pairing symmetry of some high-T_c superconductors.