2003/08/03 by Erhai Zhao, Tomas Löfwander, Tomas Lofwander +1
Engineering · Physics and Astronomy · #Molecular Junctions and Nanostructures #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.69.134503
published as Phys. Rev. B 69, 134503 (2004) · 13 pages, 8 figures
arxiv created 2003/08/03 · openalex publication_date 2004/04/08 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a comprehensive study of heat transport through small superconducting point contacts. The heat current for a temperature-biased weak link is computed as a function of temperature and barrier transparency of the junction. The transport of thermal energy is controlled by the quasiparticle transmission probability for the point contact that couples the superconducting leads. We derive this transmission probability and results for the heat current starting from nonequilibrium transport equations and interface boundary conditions for the Keldysh propagators in quasiclassical approximation. We discuss the thermal conductance for both clean and dirty superconducting leads, as well as aspects of the nonlinear current response. We show that the transmission probability for continuum quasiparticle states is both energy and phase dependent, and controlled by an interface Andreev bound state below the continuum. For high transparency barriers the formation of a low-energy bound state, when the phase is tuned to \ensuremathφ=\ensuremathπ, leads to a reduction of the heat current relative to that for \ensuremathφ=0. For low-transparency barriers, a shallow Andreev bound state just below the continuum edge is connected with resonant transmission of quasiparticles for energies just above the gap edge, and leads to enhanced heat conductance as the temperature is lowered below the superconducting transition.