Lattice dynamics and superconducting properties of antiperovskite La3InZ (Z=N,O)

Electronic and superconducting properties of La3InZ (Z=N, O) compounds are studied and are compared with La3In. From the density of states of La3InZ it is quite clear that the hybridization between La-d and In-p states gets reduced with the inclusion of the Z atom in comparison with La3In. A Fermi surface topology change is observed only in La3InO under compression, which is attributed to the non-monotonic variation of the density of states. The calculated superconducting transition temperature (Tc) is less than 2 K for N containing compound, and is found to be above 2 K for O containing compound and the trend agrees well with the experimental findings. The reason for the suppression of the Tc due to the inclusion of the Z atom is also discussed from the band structure and phonon dispersion plots, where we find the phonon modes to harden in La3InZ.