Quasiparticle lifetimes and tunneling times in a superconductor-insulator-superconductor tunnel junction with spatially inhomogeneous electrodes

A. A. Golubov; E. P. Houwman; J. G. Gijsbertsen; J. Flokstra; H. Rogalla; J. B. le Grand; P. A. J. de Korte

doi:10.1103/PhysRevB.49.12953

← Back to search

Quasiparticle lifetimes and tunneling times in a superconductor-insulator-superconductor tunnel junction with spatially inhomogeneous electrodes

A. A. Golubov, E. P. Houwman, J. G. Gijsbertsen, J. Flokstra, H. Rogalla, J. B. le Grand, P. A. J. de Korte

DOI 10.1103/PhysRevB.49.12953 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

The low-energy quasiparticle scattering and recombination lifetimes for a proximity sandwich of two superconductors S and S’ with different bulk energy gaps, are calculated as a function of the spatial coordinate and temperature. The spatial dependence of the order parameter and density of states are calculated on the basis of a microscopic model of the proximity effect, based on the Usadel equations, for dirty superconductors in thermal equilibrium. A zero boundary resistance between S and S’ and a Boltzmann-like energy distribution of the excess quasiparticles are assumed. In the case of a small diffusion time constant an effective quasiparticle relaxation rate into and excitation rate out of the reduced gap region in the SS’ sandwich are obtained as a function of (finite, but low) temperature and strength of the proximity effect, determined by the parameter γm, by averaging over the energies and positions of the quasiparticles. In the same way effective tunneling times for electrons and holes tunneling out of the trap in the SS’ sandwich to the other electrode of an SS’IS’’S junction are determined as a function of temperature, voltage, and γm.