9-13 July 2012
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
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.
Dr Walter E Meyer email@example.com