9-13 July 2012
Africa/Johannesburg timezone
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Quantum Monte Carlo (QMC) study of Pressure-induced B3-B1 phase transition in GaAs

Presented by Mr. Cecil OUMA on 12 Jul 2012 from 17:30 to 19:30
Type: Poster Presentation
Session: Poster Session
Track: Track G - Theoretical and Computational Physics

Abstract

We have investigated the transition pressure, pt , of bulk GaAs from the zinc blende (B3) to the rocksalt (B1) structure using the local density approximation (LDA), generalized gradient approximation (PBE-GGA) and diffusion Monte Carlo (DMC). We took into account finite temperature effects (zero-point vibrational effects) as well as finite size corrections. DMC projection starting from GGA trial nodal surface supports the higher value of the transition pressure (∼ 17 GPa) than the lower value of (∼ 12 GPa), both of which are experimentally reported values. This projection increases the transition pressure, pt , from DFT predictions, being of the same tendency as that for Si bulk crystal. The choice of the XC functional in DFT was found to significantly determine the phase transition pressure, DMC gave more accurate results for this transition pressure.

Award

YES

Level

PhD

Supervisor

Dr Walter E Meyer wmeyer@up.ac.za

Paper

No

Place

Location: IT Building
Room:


Primary authors

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