Structural, mechanical, electronic, and optical properties of the chalcogenide perovskite SrMS3 (M = Zr, Hf) under high pressure: A first-principles study

Chalcogenide perovskites have drawn increasing interest due to their superior optoelectronic properties. In this work, the structural, mechanical, electronic, and optical properties of the chalcogenide perovskites SrMS 3 (M = Zr, Hf) under pressure from 0 to 25 GPa are investigated using the first-principle method based on density functional theory. Both SrZrS 3 and SrHfS 3 remain mechanically stable across the entire pressure range. Their bulk modulus, shear modulus, and Young's modulus exhibit an increasing trend. It should be noted the B/G ratio exceeds 1.75, indicating intrinsic ductility — a desirable feature for device integration. Electronic property analysis shows that both SrZrS 3 and SrHfS 3 are direct bandgap semiconductors, and their bandgaps narrow steadily under pressure, leading to enhanced electrical conductivity. In addition, the optical properties gradually improve with increasing pressure. In particular, the high optical absorption at high pressures suggests potential candidates for further experimental study. Furthermore, the high reflectivity in the visible region fully indicates that the two materials are promising candidates for specialized reflective coatings.