Anticorrelation between electron-phonon coupling strength and stability of ternary metal diborides

This paper endeavors to expand the exploration of prospective superconductivity within the P6/mmm−MgB2 structural framework by substituting Mg atoms with a random selection of two distinct cations from a pool of 24 candidates. Employing a high-throughput screening methodology to scrutinize zone-center electron-phonon couplings, we found an inverse relationship between thermodynamic stability and electron-phonon coupling strength in the resulting ternary metal borides. Notably, within the MgNiB4 system, we demonstrated that electron-phonon superconductivity is stronger in less dynamically stable configurations. The qualitative reasons for the emerging instabilities when electron-phonon coupling becomes strong are discussed. This insight indicates that the quest for superior superconducting materials should concentrate on the intricate balance between electronic and phononic characteristics in structures that are on the brink of instability. locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon Physics Subject Headings (PhySH)Electronic structureAlloysHigh-temperature superconductorsFirst-principles calculations