Evolution of the specific-heat anomaly of the high-temperature superconductor YBa2Cu3O7 under influence of doping through application of pressure up to 10 GPa

TL;DR

This study investigates how applying pressure up to 10 GPa affects the specific-heat anomaly and superconducting transition temperature of YBa2Cu3O7, revealing pressure-induced charge transfer effects in a single, stoichiometric crystal.

Contribution

It demonstrates a novel pressure-based method to study doping effects and superconducting properties without introducing atomic disorder in high-temperature superconductors.

Findings

Specific-heat jump decreases with pressure.

Bulk Tc reduces with increasing pressure.

Pressure induces charge transfer affecting superconductivity.

Abstract

The evolution of the specific-heat anomaly in the overdoped range of a single crystal of the high-temperature superconductor YBa2Cu3O7 has been studied under influence of pressure up to 10 GPa, using AC calorimetry in a Bridgman-type pressure cell. We show that the specific-heat jump as well as the bulk Tc are reduced with increasing pressure in accordance with a simple charge-transfer model. This new method enables us through pressure-induced charge transfer to study the doping dependence of the superconducting transition, as well as the evolution of the superconducting condensation energy on a single stoichometric sample without adding atomic disorder.