Properties of monovacancies and self-interstitials in bcc Li: An<i>ab initi</i>pseudopotential study

Abstract

The formation energy ${\mathit{E}}_{1\mathit{V}}^{\mathit{F}}$ and the structural relaxation for a vacancy in bcc Li are calculated within the framework of the local-density approximation and the ab initio pseudopotential method for supercells, thereby correcting a small error in the pseudopotential used in former calculations. The calculated value of ${\mathit{E}}_{1\mathit{V}}^{\mathit{F}}$=0.54 eV is nearly identical to the activation energy for self-diffusion, suggesting an extraordinarily small vacancy-migration energy or a nonvacancy mechanism of self-diffusion. The results for self-interstitials exclude an interstitialcy mechanism. A local relaxation volume of -0.51 atomic volumes was found for the vacancy.