Charge embalance relaxation in superconductors at low temperatures

摘要

Charge imbalance relaxation in s-wave superconductors is studied when temperature T is much lower than the transition temperature T-c. Although the charge imbalance conversion near T-c is mainly caused by inelastic phonon scattering, it becomes less dominant with decreasing T. We study the charge imbalance conversion resulting from elastic impurity scattering in combination with pairing anisotropy. We determine the corresponding conversion time and demonstrate that the elastic process dominates the inelastic phonon process when T T-c. A qualitative picture of the charge imbalance relaxation is presented based on the conversion time and the energy relaxation time due to inelastic phonon scattering.