Linearized force constants method for lattice dynamics in mixed semiconductors

Abstract

A simple and accurate method of calculating phonon spectra in mixed semiconductors alloys, on the basis of preliminarily (from first principles) relaxed atomic structure, is proposed and tested for (Zn,Be)Se and (Ga,In)As solid solutions. The method uses an observation that the interatomic force constants, calculated ab initio for a number of microscopic configurations in the systems cited, show a clear linear variation of the main (diagonal) values of the interatomic force constants with the corresponding bond length. We formulate simple rules about how to recover the individual 3x3 subblocks of the force constants matrix in their local (bonds-related) coordinate systems and how to transform them into a global (crystal cell-related) coordinate system. Test calculations done for 64-atom supercells representing different concentrations of (Zn,Be)Se and (Ga,In)As show that the phonon frequencies and compositions of eigenvectors are faithfully reproduced in a linearized force constants calculation, as compared to true ab initio calculations.

to appear in the proceedings of the Phonons2007 conference (Paris, July 2007)

References in corpus (4)

• The SIESTA method for ab initio order-N materials simulation
• Efficient index handling of multidimensional periodic boundary conditions
• Phonons and related properties of extended systems from density-functional perturbation theory
• Lattice dynamics of mixed semiconductors (Be,Zn)Se from first-principles calculations

Cited by in corpus (1)

• Unification of the phonon mode behaviour in semiconductor alloys: Theory and ab initio calculations