First-principles study of electronic, dynamical and thermodynamic properties of Li _2TiO _3

摘要

The first-principles total energy calculations with the generalised gradient approximation and the plane-wave pseudopotential method have been employed to investigate the structural, electronic and dynamical properties of Li _2TiO _3 (lithium titanate). The atomic structure is fully relaxed, and the structural parameters are found to differ by less than 1% from the experimental data. The indirect band-gap with 3.49 eV is predicted from the band structure calculations of this compound. The calculated phonon frequencies at the L-point for the Raman-active and the infrared-active modes are presented and assigned. The phonon dispersion curves are also calculated along high symmetry lines in the Brillouin zone (BZ). Furthermore, the thermodynamic functions have been worked out using the corresponding phonon density of states, and the results indicate that they are in good agreement with available experimental values.