Pressure-induced phase transitions and electronic structure of GaAs

Abstract

The structural and electronic properties of GaAs under high pressure have beeninvestigated using an ab initio pseudo-potential approach within the framework of densityfunctional theory. We use the local density approximation based on exchange–correlationenergy optimization for calculating the total energy. The phase transition in bulk GaAs is investigated. Results of the first-principles calculation of thestructural phase transition and the electronic properties of GaAs in the three differentcrystallographic structures are reported. GaAs is found to undergo structural transitionfrom B3 to B1 phase, demonstrating a reasonably good agreement with experimentaldata. The equation of state for these transformations also shows good agreementwith experimental results. The calculated value of volume collapse is close to theobserved data. The energy of the B2 phase is found to be slightly higher thanthat of the B1 phase. A possible mechanism for the transition characterized by the space group is discussed. The calculated values show that there is a relatively small value of enthalpyfor the transition as compared to the transition, which provides the transition behaviour of GaAs from the kineticviewpoint. The electronic structures have also been computed at different volumes.