The pseudogap in Bi2212 single crystals from tunneling measurements: a possible evidence for the Cooper pairs above Tc

TL;DR

This study uses tunneling spectroscopy on Bi2212 crystals to investigate the pseudogap phenomenon, providing evidence that incoherent Cooper pairs may exist above the superconducting transition temperature.

Contribution

It presents direct tunneling measurements revealing the pseudogap and its possible link to incoherent Cooper pairs above Tc in Bi2212.

Findings

Pseudogap appears at T* = 280 K.

Pseudogap contribution disappears around 110-115 K.

Evidence suggests presence of incoherent Cooper pairs above Tc.

Abstract

We present electron-tunneling spectroscopy of slightly overdoped Bi2212 single crystals with Tc = 87 - 90 K in a temperature range between 14 K and 290 K using a break-junction technique. The pseudogap which has been detected above Tc appears at T* = 280 K. The analysis of the spectra shows that there is a contribution to the pseudogap above Tc, which disappears approximately at 110 - 115 K. We associate this contribution with the presence of incoherent Cooper pairs.