Study on the pressure-induced superconducting phases of antimony

Pressure-induced superconductivity in antimony was investigated electrically using a diamond anvil cell up to 61 GPa. A semimetal to metal transition was observed in the pressure range of 22 to 28 GPa at room temperature, which coincides with the transition from an incommensurate tetragonal host-guest structure to a body-centered cubic (bcc) structure. The high pressure metal phase was found to be superconducting and the transition temperature (T_c) was non-monotonous with regard to the applied pressure while in the bcc structure. The empirical rule, lighter elements having higher T_cs in a homologous series in non-transition elements in the periodic table, was found not to hold for bcc Sb when compared with Bi. A controlled pressure quench of the superconducting phase in the incommensurate composite phases at temperatures up to 77 K was also performed and the zero resistance was retained in the quenched phase with the midpoint of the superconducting transition above 3.4 K and a transition width of 0.2 K.