Formation enthalpies of monovacancies in aluminum and gold under the condition of intense laser irradiation

Abstract

The formation enthalpy of a monovacancy in gold and aluminum under the condition of intense laser irradiation is evaluated by means of ab initio calculations. These simulations are performed using norm-conserving pseudopotentials and by taking advantage of an efficient parallelization scheme. Using constant-pressure simulations and for a set of electronic temperatures ranging from $0.01\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}6.0\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$, fully relaxed geometries are thus obtained. Particular attention has been paid to the size of the supercell. We found that calculations up to 108 atoms are needed in order to obtain well-converged thermodynamic quantities. In this respect, the monovacancy formation enthalpy of gold increases more rapidly than for aluminum at high electronic temperatures, leading to a reduction of the monovacancy concentration. This result confirms the increase of the melting temperature and is in good agreement with ab initio linear response calculations previously reported.