Pressure-induced phase transition and electronic properties of CdPX₃ (X = S and Se) by first-principles calculation

The two-dimensional (2D) transition metal thiophosphates family CdPS₃ and CdPSe₃ are supposed to explore pressure-relevant structural and electronic behaviors as support to build 2D spintronic devices. The pressure-induced phase transition and electronic properties of CdPX₃ are investigated up to 40 GPa using first-principles calculation. CdPS₃ undergoes reversible phase transitions at around 1.5 GPa and 25 GPa from C₂/m structure to structure and then to \(P\overline{3} 1m\) structure, while the reversible phase transitions of CdPSe₃ are found at approximately 13 GPa from \(R\overline{3}\) structure to \(P\overline{3} 1m\) structure, reflected in the lattice constant mutation and cell volume collapse. The computed metallization transition is found at about 25 GPa and 13 GPa owing to energy band closure for CdPS₃ and CdPSe₃, respectively. As anisotropy increases with pressure, the enhanced metallic property is accompanied by the inter- and intra-layer sliding atom pairs induced by phase transition. The paper is conducive to considering the phase transition and metallization of CdPX₃-type family under extreme conditions.