Pressure-induced disordered substitution alloy in Sb₂Te ₃

A new type of disordered substitution alloy of Sb and Te at above 15.1 GPa was discovered by performing in situ high-pressure angle-dispersive X-ray diffraction experiments on antimony telluride (Sb₂Te₃), a topological insulator and thermoelectric material, at room temperature. In this disordered substitution alloy, Sb₂Te₃ crystallizes into a monoclinic structure with the space group C2/m, which is different from the corresponding high-pressure phase of the similar isostructural compound Bi ₂Te₃. Above 19.8 GPa, Sb₂Te₃ adopts a body-centered-cubic structure with the disordered atomic array in the crystal lattice. The in situ high-pressure experiments down to about 13 K show that Sb₂Te₃ undergoes the same phase-transition sequence with increasing pressure at low temperature, with almost the same phase-transition pressures.