Effect of magnetic field on impurity bound states in high-Tc superconductors

Abstract

The influence of magnetic field H on the quasiparticle bound states near strong impurities in d-wave superconductors is considered. At large but finite impurity strength, there are corrections to the energy and width of the impurity-induced resonance, proportional to H2. In the limit of very strong impurity potential (unitary limit), the bound state is destroyed and acquires a finite width which depends non-analytically on H. There are also considerable changes in the asymptotic behaviour of the bound state wave functions, which might affect the quasiparticle transport in HTSC.