Ginzburg-Landau theory of superconducting surfaces under electric fields
  A boundary condition for the Ginzburg-Landau wave function at surfaces biased by a strong electric field is derived within the de Gennes approach. This condition provides a simple theory of the field effect on the critical temperature of superconducting layers. 
P. Lipavsky, K. Morawetz, J. Kolacek, T. J. Yang