Suppression of the superconducting energy gap in intrinsic Josephson junctions of $\mathbf{Bi_2Sr_2CaCu_2O_{8+\delta}}$ single crystals

TL;DR

This study investigates how high bias currents affect the superconducting energy gap in intrinsic Josephson junctions of Bi-2212 crystals, revealing suppression mechanisms related to nonequilibrium effects and device geometry.

Contribution

It provides new insights into the suppression of the energy gap and super-current reentrance phenomena in intrinsic Josephson junctions under high bias conditions.

Findings

Energy gap suppression varies with temperature.

Suppression depends on electrode size.

Reentrant super-current observed at high bias.

Abstract

We have observed back-bending structures at high bias current in the current-voltage curves of intrinsic Josephson junctions. These structures may be caused by nonequilibrium quasiparticle injection and/or Joule heating. The energy gap suppression varies considerably with temperature. Different levels of the suppression are observed when the same level of current passes through top electrodes of different sizes. Another effect which is seen and discussed, is a super-current ``reentrance'' of a single intrinsic Josephson junction with high bias current.