ROLE OF ELECTRON-PHONON INTERACTION IN LATTICE-DYNAMICS AND SUPERCONDUCTIVITY OF OXIDE SPINEL LITI2O4

The lattice dynamics of an oxide spinel LiTi2O4 is studied by taking a ccount of the electron-phonon (EP) interaction derived on the basis of the realistic tight-binding bands fitted to the first-principles band s. Due to the characteristic dependences of the EP interaction on wave vectors and vibrational modes, a remarkable frequency renormalization of the O vibrational modes, which hybridize with the Ti vibrational mo des, is obtained over a wide region of the Brillouin zone. The overall features of the calculated phonon density of states are in agreement with those observed by the inelastic neutron scattering measurements. By using the EP interaction and the renormalized phonon frequencies we have calculated the EP spectral function alpha2F(omega)). The superco nducting transition temperature, gap function, and tunneling spectra a re calculated by solving the Eliashberg equation. The results agree we ll with the observations.