Theory of Nonequilibrium Superconductivity

Abstract This book presents modern theory of nonstationary and nonequilibrium superconductivity. It deals with superconductors in external fields varying in time and studies transport phenomena in superconductors. The book provides the microscopic theory based on the Green function formalism within the Bardeen, Cooper, and Schrieffer (BCS) theory. The method of quasiclassical Green functions is formulated for both stationary and nonequilibrium problems in the theory of superconductivity. Chapters 1 to 4 give an introduction to the Green function formalism in the BCS theory for clean materials and alloys. In next two chapters, the quasiclassical approximation is introduced and applied to some generic stationary problems such as the Ginzburg–Landau (GL) equations, critical magnetic fields, gapless superconductivity, d-wave superconductivity, bound states in the vortex core. Chapter 7 describes the quasiclassical method for layered superconductors. In Chapter 8 the nonstationary theory is formulated using both the method of analytical continuation and the Keldysh diagram technique. Next two chapters are devoted to the quasiclassical approximation and to generalized kinetic equations in nonstationary situations. Chapter 11 demonstrates how the GL model can be extended to nonstationary problems. A considerable part of the book is devoted to the vortex dynamics, which treats behaviour of type II superconductors when they carry electric currents in presence of a magnetic field. Chapters 12 to 15 deal with the dynamics of vortices. In Chapter 12, the time-dependent GL model is used to calculate the resistivity in the flux flow regime. Chapter 13 derives the forces acting on a moving vortex using the Green function formalism and applies the microscopic theory to the vortex dynamics in superconducting alloys. In Chapters 14 and 15 the vortex dynamics in clean superconductors is considered and the flux-flow conductivity, the vortex Hall effect, and the vortex mass are calculated.