Quantum Monte Carlo study of pressure-inducedB3−B1phase transition in GaAs

Abstract

We have investigated the transition pressure, p t , 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. Our DMC calculation using 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, p t , 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, while DMC gave more accurate results for this transition pressure.

First-Principles Study of Structural Transitions in LiNiO2 and High-Throughput Screening for Long Life Battery

“…The increasing trend for 0 < x < 0.8 was attributed to the reduced ionic interactions caused by the charge reduction in the Ni−O layer by the oxidation of Ni 3+ to Ni 4+ . The large overestimations of the PBE lattice constants can be primarily attributed to the general tendency of PBE to afford underbindings 46 and to the lack of vdW interlayer attractions that only the vdW-XC considered. Since the contribution of the vdW forces to the cohesion was estimated to be approximately 1−2%, 47 the difference in the plot (Figure 2) of approximately 1% is reasonable.…”

Symmetry of the Non-Atomic Interactions of N-Atomic Energy and the Atomistic Theory of High-Order Elastic Modules

“…Twenty-two adjustable parameters were used in [12] to obtain results in the EAM approximation. Thirty-two adjustable parameters were used in [17] for Monte Carlo calculations using the nonlocal pseudopotential model (Table 2). So-called "semiempirical" [18] or "molecular" [19] models, in which energies of pair and multiatomic interaction are postulated without referring to the quantum state of isolated atoms [20], are employed no less frequently than the widely used models of quantum chemistry.…”

“…Quantum and molecular models of the energies of pair interaction coincide at the necessary first step of the theory. One difference is that models of quantum chemistry require more phenomenological parameters for their determination [12,13,17]. If we include triplets, quadruplets, and larger groups in the theory of irreducible energies of interaction, molecular models have a number of advantages over approximated calculations in the models of quantum chemistry.…”

Diffusion Monte Carlo Study of Para-Diiodobenzene Polymorphism Revisited

“…Many large-scale periodic QMC simulations have been performed. − They show that the above-mentioned schemes work well for isotropic (mostly cubic) systems having small unit cells with only one or two elements. QMC applications to molecular crystals have been traditionally restricted to relatively simple systems, e.g., phase diagrams of ice and solid molecular hydrogen .…”