Impurity Quantum Phase Transition in a Current-Carrying d-Wave   Superconductor
  We study an Anderson impurity embedded in a d-wave superconductor carrying a supercurrent. The low-energy impurity behavior is investigated by using the numerical renormalization group method developed for arbitrary electronic bath spectra. The results explicitly show that the local impurity state is completely screened upon the non-zero current intensity. The impurity quantum criticality is in accordance with the well-known Kosterlitz-Thouless transition. 
Hua Chen, Yezheng Wu, Shuxiang Yang, Jianhui Dai, Jian-Xin Zhu