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Single interface effects dominate in exciton-condensate/normal-barrier/exciton-condensate (EC/N/EC) structures of long-barrier

Research paper by Ya-Fen Hsu, Jung-Jung Su

Indexed on: 05 Aug '18Published on: 01 Aug '18Published in: New journal of physics



Abstract

We study theoretically the exciton-condensate/normal-barrier/exciton-condensate (EC/N/EC) structures in bilayers with a tunable relative phase ϕ 0 between the two exciton condensates (ECs). It is a setup inspired initially by the superconducting Josephson junction but with a special ingredient added for bilayer systems, namely, the interlayer tunneling . Our results shows that in a EC/N/EC structure of long-barrier, the single Andreev reflection at one EC/N interface dominates—as opposed to the same structure of short-barrier , in which multiple Andreev reflections can be accommodated (similar to the superconducting Josephson junctions). The single interface effect turns the other EC inert and the system can no longer be understood as a Josephson junction. The supercurrent, however, still occurs at the N/EC interface since the current conservation is still fulfilled with the assistance of the interlayer tunneling in barriers. This exotic mechanism g...