Physical properties of Cr₂S₃ at high pressure

The compressive behavior of Cr₂S₃ in a quasi-hydrostatic environment was investigated by synchrotron x-ray diffraction using silicone oil as the pressure-transmitting medium in a diamond anvil cell. The maximum pressure was 34 GPa. We found that Cr₂S₃ undergoes a structural phase transition at a pressure of 8.5 GPa and the bulk modulus before the phase transition was fitted to be 88 GPa, which corresponds to a bulk modulus of 67 GPa calculated by first-principles theory. In addition, we also investigated the electrical resistance of Cr₂S₃ at different pressures and temperatures and found that the resistance decreases rapidly with increasing pressure or temperature and then remains almost unchanged with an increase in pressure or temperature. This indicates that Cr₂S₃ undergoes a structural phase transition around 8 GPa. In order to accurately confirm the phase transition pressure, high-pressure Raman experiments were used. We found that the position of Raman peak 3 increases approximately linearly at low pressure and remains constant above 8 GPa, indicating that a structural phase transition occurs at 8 GPa. Finally, the deviatoric stress of Cr₂S₃ at high pressures was investigated by the linewidth analysis method. The results show that the deviatoric stress increases approximately linearly at low pressures in the range of 2.8–6.2 GPa.