Sb(2)Se(3) under pressure

Selected members of the A(2)B(3) (A = Sb, Bi; B = Se, Te) family are topological insulators. The Sb(2)Se(3) compound does not exhibit any topological properties at ambient conditions; a recent high-pressure study, however, indicated that pressure transforms Sb(2)Se(3) from a band insulator into a topological insulator above ~2 GPa; in addition, three structural transitions were proposed to occur up to 25 GPa. Partly motivated by these results, we have performed x-ray diffraction and Raman spectroscopy investigations on Sb(2)Se(3) under pressure up to 65 GPa. We have identified only one reversible structural transition: the initial Pnma structure transforms into a disordered cubic bcc alloy above 51 GPa. On the other hand, our high-pressure Raman study did not reproduce the previous results; we attribute the discrepancies to the effects of the different pressure transmitting media used in the high-pressure experiments. We discuss the structural behavior of Sb(2)Se(3) within the A(2)B(3) (A = Sb, Bi; B = Se, Te) series.