# Point-contact spectroscopy of superconducting YBaCuO single crystals of tetragonal modification

## TL;DR

This study investigates the point-contact spectra of tetragonal YBaCuO superconductors, revealing the energy gap, its temperature dependence, and the interaction with phonons, suggesting a temperature-increasing pair gap near the critical temperature.

## Contribution

It provides new insights into the quasiparticle excitations and phonon interactions in tetragonal YBaCuO superconductors through point-contact spectroscopy.

## Key findings

- Determined the single-electron energy gap ($2\Delta_0/kT_c \\simeq 17$).
- Found correlation between quasiparticle energies and phonon energies.
- Discovered a pair gap increasing with temperature near $T_c$.

## Abstract

The point-contact spectra of tetragonal $\rm YBa_2Cu_3O_{7-\delta}$ with $T_c=50-60~K$ are studied at various temperatures. The single-electron energy ($2\Delta_0/kT_c\simeq 17$) and its temperature dependence are determined. The characteristic energies of quasiparticle excitations interacting with conduction electrons in this high-$T_c$. superconductor are found to correlate with the characteristic phonon energies. The possibility of a pair gap, which increases with temperature, is revealed near the critical temperature.