Structural, Vibrational, and Electronic Study of Sb₂S₃ at High Pressure

Antimony trisulfide (Sb₂S₃), found in nature as the mineral stibnite, has been studied under compression at room temperature from a joint experimental and theoretical perspective. X-ray diffraction and Raman scattering measurements are complemented with ab initio total-energy, lattice-dynamics, and electronic structure calculations. The continuous changes observed in the volume, lattice parameters, axial ratios, bond lengths, and Raman mode frequencies as a function of pressure can be attributed to the different compressibility along the three orthorhombic axes in different pressure ranges, which in turn are related to the different compressibility of several interatomic bond distances in different pressure ranges. The structural and vibrational properties of Sb₂S₃ under compression are compared and discussed in relation to isostructural Bi₂S₃ and Sb₂Se₃. No first-order phase transition has been observed in Sb₂S₃ up to 25 GPa, in agreement with the stability of the Pnma structure in Bi₂S₃ and Sb₂Se₃ previously reported up to 50 GPa. Our measurements and calculations do not show evidence either for a pressure-induced second-order isostructural phase transition or for an electronic topological transition in Sb₂S₃.