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

We derive a general microscopic expression for the nonlinear diamagnetic current in clean superconductor-insulator-normal metal structures 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 $T=0.\mathrm{}$ 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.