2008/08/31 by Aditi Mitra
Materials Science · Physics and Astronomy · #Condensed matter physics #Coupling (piping) #Dissipative system #Electron #Magnetic and transport properties of perovskites and related materials #Non-equilibrium thermodynamics #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Scaling #Superconductivity #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.78.214512
published as Phys. Rev. B 78, 214512 (2008) · 18 pages, 1 figure, discussion added
arxiv created 2008/12/18 · openalex publication_date 2008/12/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present a microscopic derivation of the effect of current flow on a system near a superconductor-metal quantum critical point. The model studied is a 2d itinerant electron system where the electrons interact via an attractive interaction and are coupled to an underlying normal metal substrate which provides a source of dissipation and also provides a source of inelastic scattering that allows us to reach a nonequilibrium steady state. A nonequilibrium Keldysh action for the superconducting fluctuations on the normal side is derived. Current flow, besides its minimal coupling to the order parameter, is found to give rise to two effects. One is a source of noise that acts as an effective temperature Teff=eEvF\ensuremathτsc, where E is the external electric field, vF is the Fermi velocity, and \ensuremathτsc is the escape time into the normal metal substrate. Second current flow also produces a drift of the order parameter. Scaling equations for the superconducting gap and the current are derived and are found to be consistent with previous phenomenological treatments as long as a temperature T\ensuremath∼Teff is included. The current induced drift is found to produce additional corrections to the scaling which are smaller by a factor of O(\frac1EF\ensuremathτsc), with EF being the Fermi energy.