Quasiparticle behavior in tunnel junction refrigerators

摘要

We present simulations of quasiparticle creation, propagation, and loss in the211u001esuperconducting electrode of a normal-insulator-superconductor tunnel junction 211u001erefrigerator. We calculate the electronic temperature in the superconducting 211u001eelectrode from self-consistent solutions to the diffusion equation. We then 211u001ecalculate the power load on the normal electrode due to recombination phonons and 211u001ethe reduction in cooling power due to the elevated temperature of the 211u001esuperconductor. Our calculations explain the degraded cooling performance 211u001eobserved in 15-20 pm sized Ag/AlOx/Al junctions.