Superconductivity in Chevrel phases

Chevrel phases is a class of interesting materials discovered more than 40 years ago including more than 100 examples.
They are ternary compounds of general stoichiometry M_xMo₆X₈ (X = chalcogen and M=metal) and many of them show interesting superconducting properties with critical temperatures as high as 15K and high critical magnetic fields (arount 50 Tesla).
We present the results of the prediction of the superconducting phase in Chevrel compound, PbMo₆S_8, within the SuperConducting Density Functional Theory (SCDFT), a first-principles theory of the superconducting phase which does not rely on any semi-empirical parameter.
We succesfully predict the critical temperature of PbMo₆S₈ at ambient conditions highlighting the role of phase instability, electron-phonon coupling with different intra-molecular and inter-molecular phonon modes and the fundamental role of repulsive electron-electron interaction, treated from first-principles. The evolution of the superconducting critical temperature as a function of the external pressure results in excellent agreement with available experiments.
Despite the interesting physical and chemical properties of Chevrel phases their fundamental explanation was still lacking: SCDFT opens way to systematic investigation of this large class of compounds.