Highly compressed Miassite Rh 17 S 15 : A Bose-Einstein condensate superconductor?

Abstract

Miassite (the 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. (PRB 111, L161113 (2025)) reported that the Tc in Rh15S17 at pressure range 2.5 GPa < P < 60 GPa is suppressed below 2.5 K. However, at pressure above P > 60 GPa the superconducting state reentrants and the highest transition temperature of Tc = 5 K was observed at P = 117.7 GPa. Here, I have analyzed the reported experimental temperature and magnetic field dependences of the resistance R(T,P,B) in highly compressed Rh15S17. 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, which is surprisingly close to the Bose-Einstein condensate ratio Tc/TF = 0.176.

Keywords: Bose-Einstein condensate, high-pressure superconductivity