Dresden 2009 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 3: Mechanical Properties I

MM 3.3: Talk

Monday, March 23, 2009, 11:00–11:15, IFW B

Anharmonic contributions to the phonon density of states of rock-salt AlN — •Steve Schmerler and Jens Kortus — TU Bergakademie Freiberg, Institut für Theoretische Physik, Leipziger Str. 23, 09599 Freiberg, Germany

The standard approach to calculate the phonon dispersion of crystals by means of density functional theory is based on the harmonic approximation. Unfortunately, this method is limited to 0 K calculations and neglects anharmonic contributions completely.

Molecular dynamics simulations allow to obtain the phonon density of states (PDOS) by Fourier transformation of the velocity auto-correlation function. This route opens the way to study phases at various temperatures and also includes anharmonic contributions to the PDOS.

We compare the results of both methods in case of several AlN phases, which are of recent experimental and theoretical interest. In particular we focus on the vibrational properties of the cubic AlN phase.

We would like to thank the DFG for financial support within the DFG Priority Program 1236: Strukturen und Eigenschaften von Kristallen bei extrem hohen Drücken und Temperaturen