The electrical properties of Cd2Re2O7 under pressure

TL;DR

This study investigates how pressure affects the electrical properties and phase transitions of Cd2Re2O7, revealing pressure-sensitive anomalies and phase boundary behavior up to 1.2GPa.

Contribution

It provides detailed measurements of resistivity and thermopower under pressure, identifying new phase transition features and their evolution with pressure in Cd2Re2O7.

Findings

Thermopower is highly sensitive to phase transitions.

A second phase transition occurs at 125K.

The phase boundary drops to zero before 1.8GPa.

Abstract

We examine the resistivity and thermopower of single crystal specimens of the pyrochlore oxide Cd2Re2O7 at pressures up to 2GPa. Thermopower proves to be a sensitive tool in the study of the phase diagram of Cd2Re2O7. The 200K metal-to-metal phase transition is accompanied by a strong increase of the absolute value of the thermopower. A weaker anomaly allows to identify a second phase transition at 125K. Following the temperature dependence of this anomaly, we obtain the corresponding phase boundary up to 1.2GPa, and argue that it must drop to T=0 before p reaches 1.8GPa. There is a wide temperature range where the electrical properties are fairly sensitive to pressure, indicating the strong coupling of the electronic degrees of freedom to the lattice.