Diffusion Monte Carlo Re-evaluation of Bulk Aluminium with QMCPACK

In the past decades, diffusion Monte Carlo (DMC) has proven to be one of the most accurate ab initio methods for molecules and solids. Its parallel algorithm enables efficient use of High Performance Computing (HPC) facilities around the world. In 2012, a DMC study on bulk aluminium with the CASINO code developed by the Theory of Condensed Matter group in University of Cambridge[1] was one of the first calculations on a solid using modern algorithms, corrections to finite size effects, and time step extrapolation. Good agreement with experimental data was achieved, exceeding by far, those obtained by Density Functional Theory (LDA and GGA exchange correlation functionals).
We have revisited bulk aluminium energetics using the QMCPACK code developed in United States and optimized for leadership class Computing facilities. Using new HPC oriented algorithms, twist averaged boundary conditions along with finite-size corrections, we have obtained excellent agreement with experiments and previous data at a fraction of the cost of previous calculations. This reduction of the cost enabled the accurate study of defect and pair defect energies of bulk aluminum.

Keywords: ab initio, Diffusion Monte Carlo, QMCPACK, bulk, aluminium, defects

Reference:
[1] R. Hood et al., PRB 85 134109 (2012)