Interstitial anionic electrons favoring superconductivity in Li-As electrides

Abstract

Interstitial anionic electrons (IAEs) at lattice cavities of electrides, which have diverse morphologies and concentrations, can induce interesting physical and chemical properties. Understanding the correlation between IAEs and electron-phonon coupling is crucial for the development of new electride superconductors. We have applied first-principles structural search calculations to predict new high-pressure Li-As electrides, such as $P6/mmm {\mathrm{Li}}_{x}\mathrm{As}$ ($x=5$ and 8), ${\mathrm{Li}}_{6}\mathrm{As}$ with $Cmc{2}_{1}$ and $C2/c$ symmetries, and $C2/m\phantom{\rule{0.16em}{0ex}}{\mathrm{Li}}_{10}X$ ($X=\mathrm{As}$ and Sb), which together with the already known $C2/m\phantom{\rule{0.16em}{0ex}}{\mathrm{Li}}_{10}\mathrm{Te}$ compound present favorable characteristics (i.e., variable donor content, structural symmetries, and acceptor species) to explore IAE-related superconductivity. According to our results, the predicted superconducting temperatures of these electrides are positively correlated with the number and connectivity of IAEs.