High-Throughput Screening of Strong Electron-Phonon Couplings in Ternary Metal Diborides

We perform a high-throughput screening on phonon-mediated superconductivity in a ternary metal diboride structure with alkali, alkaline earth, and transition metals. We find 17 ground states and 78 low-energy metastable phases. From fast calculations of zone-center electron-phonon coupling, 43 compounds are revealed to show electron-phonon coupling strength higher than that of MgB2. An anticorrelation between the energetic stability and electron-phonon coupling strength is identified. We suggest two phases, i.e., Li3ZrB8 and Ca3YB8, to be synthesized, which show reasonable energetic stability and superconducting critical temperature.

Automated summary

In this study, we conducted a high-throughput screening on phonon-mediated superconductivity in a ternary metal diboride structure with alkali, alkaline earth, and transition metals. We identified 17 ground states and 78 low-energy metastable phases. Fast calculations of zone-center electron-phonon coupling revealed that 43 compounds have higher electron-phonon coupling strength than MgB2. An inverse correlation between energetic stability and electron-phonon coupling strength was discovered. We suggest synthesizing two phases, Li3ZrB8 and Ca3YB8, which exhibit reasonable energetic stability and superconducting critical temperature.