Electron-phonon coupling and superconducting critical temperature of the YIr2Si2 and LaIr2Si2 high-temperature polymorphs from first-principles

Ab initio calculations of the electronic structure and lattice-vibrational properties were performed on the superconducting high-temperature polymorphs of YIr2Si2 and LaIr2Si2. The electron–phonon coupling constants λep were found to be 0.61 and 0.56 for YIr2Si2 and LaIr2Si2, respectively. The superconducting critical temperatures estimated from the Allen–Dynes formula agree well with the available experimental data and indicate that the superconductivity in these compounds can be explained by intermediate strength electron–phonon coupling.