Pressure-induced structural phase transition in the Bechgaard-Fabre salts

TL;DR

This study investigates how applying pressure causes structural phase transitions in specific quasi-one-dimensional organic salts, revealing anomalies in their crystal structures at high pressures up to 10 GPa.

Contribution

The paper reports the first detailed pressure-dependent x-ray diffraction analysis of (TMTTF)$_2$PF$_6$ and (TMTSF)$_2$PF$_6$, identifying the pressures at which structural phase transitions occur.

Findings

Structural phase transitions occur at 8.5 GPa for (TMTTF)$_2$PF$_6$

Structural phase transitions occur at 5.5 GPa for (TMTSF)$_2$PF$_6$

Unit-cell parameters show anomalies at transition pressures

Abstract

The crystal structures of the quasi-one-dimensional organic salts (TMTTF)$_2$PF$_6$ and (TMTSF)$_2$PF$_6$ were studied by pressure-dependent x-ray diffraction up to 10 GPa at room temperature. The unit-cell parameters exhibit a clear anomaly due to a structural phase transition at 8.5 and 5.5 GPa for (TMTTF)$_2$PF$_6$ and (TMTSF)$_2$PF$_6$, respectively.