Theory of Nonlinear Meissner Effect in High-Temperature Superconductors

We investigate the nonlinear Meissner effect microscopically. Previous studies did not consider a certain type of interaction effect on nonlinear phenomena. The scattering amplitude barely appears without being renormalized into the Fermi-liquid parameter. With this effect we can solve the outstanding issues (the quantitative problem, the temperature and angle dependences of the nonlinear effect). The quantitative calculation is performed with the use of the fluctuation-exchange approximation on the Hubbard model. It is also shown that the perturbation expansion on the supercurrent by the vector potential converges owing to the nonlocal effect