Pressure effect on the electrical properties of the ladder compounds (DT-TTF)2[M(mnt)2], M=Au, Pt, Ni

The electrical conductivity under pressures up to 25 kbar of the ladder compounds (DT-TTF)2[M(mnt)2], M=Au, Pt, Ni is reported. All compounds display a large pressure effect in the conductivity. The M=Au compound which is a semiconductor at ambient pressure, becomes metallic above 15 kbar with a behaviour similar to the other members of this family at ambient pressure and high temperatures. The M=Ni and Pt compounds present an anomaly around 17 kbar in both the pressure dependencies of the metal–insulator transition temperature and the low temperature activation energy ascribed to a structural change.