Structure dependent phonon properties of LaMnO3

We have reported the results of our theoretical investigations on the vibrational properties of LaMnO3 in its cubic structure by using lattice dynamical simulation method based on the rigid ion model to understand the role of phonons in these systems. The calculated zone centre frequencies agree reasonably well with the available data. The phonon dispersion curves, phonon density of states and lattice specific heat are also reported for the cubic LaMnO3. We also report the phonon properties for LaMnO3 in its rhombohedral structure and compare them with the cubic phase phonon properties. The phonon properties are different in these two phases of LaMnO3 compound. The shift in peak position and appearance of new peaks are also observed in phonon density of states. The low temperature specific heat is different due to the difference in the behaviour of lower frequency phonon modes.