Fizika Nizkikh Temperatur: Volume 47, Number 12 (December 2021), p. 1079-1089 ( to contents , go back )
Reentrant superconductivity in a hybrid heterostructure with a high transparency barrier
E. E. Zubov
G. V. Kurdyumov Institute for Metal Physics, National Academy of Science of Ukraine, Kyiv 03142, Ukraine
Department for Research, Joint Research Laboratory for Dynamics of Electronic Processes in Hybrid Structures, Vasyl’ Stus Donetsk National University, Vinnytsia 21021, Ukraine
Received June 22, 2021, published online October 25, 2021
Within the framework of the self-consistent effective field approximation of the time-dependent perturbation theory, an influence of the electron tunneling on the spontaneously induced order parameters in a normal metal–superconductor hybrid structure is considered. For a normal-metal model, which does not take into account electron-electron scattering, as well as electron-phonon coupling, a critical barrier transparency, corresponding to the disappearance of superconductivity in the ground state, was obtained. The presence of incoherent excitations leads to a complex relationship between the effects of ordering, thermal fluctuations, and tunneling. Near the critical barrier transparency, this can stabilize a superconducting state in the certain temperature intervals. As a result, a reentrant superconductivity phenomenon was observed. The studied spectral properties of the hybrid structure reflect the existence of both coherent and incoherent elementary excitations.
Key words: superconductivity, critical temperature, hybrid structure, tunnel barrier, proximity effect, coherence effect.