Electron-phonon interaction, lattice dynamics and superconductivity of an oxide spinel LiTi₂O₄

The electron-phonon interaction of an oxide spinel LiTi₂O ₄ is calculated on the basis of a realistic electronic band structure, which is obtained by the tight-binding model so as to reproduce the first-principles bands. The lattice dynamics of LiTi₂O₄ is studied by taking account of the effect of the electron-phonon interaction. Due to the characteristic dependences of the electron-phonon interaction on wavevectors and vibrational modes, a remarkable phonon frequency renormalization is found in the frequency range of 30-80 meV over a wide region of the Brillouin zone. By using the electron-phonon interaction and the renormalized phonon frequencies, the electron-phonon spectral function alpha ²F( omega ) is calculated to provide a basis for understanding the superconductivity of LiTi₂O₄. The superconducting transition temperature, gap functions, tunneling spectra and other thermodynamic properties are studied by solving the Eliashberg equation. The calculated results are in good agreement with observations.