First principles study of isostructural phase transition in Sb₂Te₃ under high pressure

The structural properties, electronic band structure and Bader charge of Sb₂Te₃ under hydrostatic pressure were simulated using density functional theory in order to study isostructural phase transitions (IPT) in Sb₂Te₃. The theoretical results showed that the axial ratio c /a did not exhibit any anomaly below 6 GPa. The variations of bond lengths were discontinuous at 2.5 GPa, which suggested considerable changes in interatomic interactions and provided sound support to the IPT. The effective charges of Sb and Te atoms showed significant discontinuous variations at 2.5 GPa, which revealed a strong redistribution of the electronic charge density and considerably changed interactions among bonding atoms. Thus, the IPT is originated from the considerable variation in the electronic charge density.