High-pressure Raman study on the superconducting pyrochlore oxide Cd2Re2O7

TL;DR

This study uses high-pressure Raman scattering to explore structural transitions in the superconducting pyrochlore oxide Cd2Re2O7, revealing symmetry changes and phase behavior up to 4.8 GPa.

Contribution

It provides new insights into pressure-induced structural phase transitions and symmetry restoration in Cd2Re2O7 using Raman spectroscopy.

Findings

Structural transition at 1.9-3.0 GPa observed

Inversion symmetry recovers above 4.2 GPa

Pressure influences structural phases and symmetry

Abstract

The superconducting pyrochlore oxide Cd2Re2O7 (Tc = 1 K), which is now considered as a candidate of the spin-orbit-coupled metal, shows an inversion-symmetry-breaking structural transition at Ts1 = 200 K. Ts1 decreases with increasing pressure and disappears at around Pc = 4:2GPa, where at least four high-pressure phases with tiny structural distortions are suggested by means of powder X-ray diffraction [Yamaura PRB 2017]. We have carried out Raman scattering experiments to investigate changes in the crystal symmetry under high pressures up to 4.8 GPa. A structural transition at 1.9-3.0 GPa and the recovery of inversion symmetry above Pc are observed at 12 K.