Dresden 2011 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 12: Postersitzung I

MM 12.25: Poster

Monday, March 14, 2011, 17:30–19:00, P5

Density functional theory study of LO-TO splitting of vibrational modes of insulating compounds — •Marcel Hieckel, David Reith, and Raimund Podloucky — Faculty of Chemistry, Univ. Vienna

We present results of density functional theory (DFT) calculations for vibrational properties of insulating compounds derived by the force constant method [1]. For the exchange-correlation functional the generalized gradient approximation as well as a hybrid functional were used. The LO-TO splitting in ionic solids is due to the long range Coulomb interactions which is caused by the coupling of atomic displacements to the thus generated electrostatic field [2]. The modelling is based on an additional nonanalytic term to the dynamical matrix which depends on the Born effective charges and the dielectric constant whose tensors are derived from DFT calculations of the macroscopic electronic polarization [3]. The results for nonmagnetic ionic compounds are as well as for the transition metal oxides MnO and NiO are presented and compared to experiment. [1] D. Reith, program package fPHON based on PHON by D. Alfè, 1998. [2] M. Born and K. Huang, Dynamical Theory of Crystal Lattices, Oxford University Press, 1954. [3] R.W. Nunes and X. Gonze, Xavier, Phys. Rev. B 63, 155107 (2001).