Solubility and diffusivity of hydrogen and its isotopes in the BeO system

Abstract

This work revisits hydrogen insertion in the wurtzite beryllium oxide in order to fill the gap in scientific knowledge regarding the diffusion coefficients of the different chemical states of hydrogen (neutral, charged, or molecular). Both first-principle and macroscopic models were used to this end. In the former, two exchange-correlation functionals (PBE and SCAN) were used to compute the properties of interest and accuracy was then discussed. Regarding the behavior of interstitial insertion of hydrogen, this work is slightly different from previous works; hydrogen was mainly found in the form of charged H− or H+ ions, depending on experimental conditions. In regard to diffusivity properties, a complex migration pathway was found for hydrogen cation. Finally, the present study succeeded in producing a reliable set of diffusion coefficients for neutral, charged, and molecular hydrogen.