Proximity-induced screening and its magnetic breakdown in mesoscopic hybrid structures

TL;DR

This paper derives a microscopic expression for the non-linear diamagnetic current in superconductor-insulator-normal metal structures, analyzing how interface transmission affects magnetic screening and breakdown.

Contribution

It provides a new microscopic formula for the non-linear diamagnetic current and explores the effects of interface transmission on magnetic breakdown in hybrid structures.

Findings

Diamagnetic response increases monotonously with decreasing temperature.

Magnetic breakdown field is suppressed at low interface transmissions.

Linear diamagnetic current is independent of barrier transmission at low temperatures.

Abstract

We derive a general microscopic expression for the non-linear diamagnetic current in a clean superconductor-insulator-normal metal structure with an arbitrary interface transmission. In the absence of electron-electron interactions in the normal metal the diamagnetic response increases monotonously with decreasing temperature showing no sign of paramagnetic reentrance down to T=0. We also analyze the magnetic breakdown of proximity induced Meissner screening. We demonstrate that the magnetic breakdown field should be strongly suppressed in the limit of small interface transmissions while the linear diamagnetic current does not depend on the transmission of the insulating barrier at low enough temperatures.