Highly Compressed Miassite Rh17S15: A Bose–Einstein Condensate Superconductor?

Miassite (rhodium sulfide Rh17S15) is the mineral with the highest superconducting transition temperature Tc = 5.5 K among other minerals. Laboratory-grown Rh17S15 phase has been studied by several groups, but the superconductivity in Rh17S15 is still not fully understood. Recently, Xu et al. 10 reported that the Tc in Rh17S15 at pressure range 2.5 GPa 60 GPa the superconducting state reentrants and the highest transition temperature of Tc = 5 K was observed at P = 117.7 GPa. Here, the reported experimental temperature and magnetic field dependences of the resistance R(T, P, B) in highly compressed Rh17S15 were analyzed. As a result, I found that the ratio of the superconducting transition temperature, Tc, to the Fermi temperature, TF, in Rh17S15 at P = 110 GPa is Tc/TF = 0.150–0.167 that is surprisingly close to the Bose–Einstein condensate ratio Tc/TF = 0.176.