Phase Modulated Thermal Conductance of Josephson Weak Links
Erhai Zhao, Tomas Löfwander and J. A. Sauls
- Address: Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208
- Date: September 2, 2003
Physical Reivew Letters 91, 077003 (2003)
We present a theory for quasiparticle heat transport through superconducting weak links.
The thermal conductance depends on the phase difference (φ) of the superconducting leads.
Branch conversion processes, low-energy Andreev bound states near the contact and the
suppression of the local density of states near the gap edge are related to phase-sensitive
transport processes. Theoretical results for the influence of junction transparency, temperature
and disorder, on the phase modulation of the conductance are reported. For high-transmission
weak links, D → 1, the formation of an Andreev bound state at
εb = Δ cos(φ/2) leads to suppression
of the density of states for the continuum excitations that transport heat, and thus, to a reduction
in the conductance for φ = π. For low-transmission (D ≪ 1) barriers resonant scattering
at energies ε = (1+D/2)Δ leads to an increase in the thermal conductance as T drops
below Tc (for phase differences near φ = π).
- Comment: 4 pages with 3 figures