Interstitial anionic electrons favoring superconductivity in Li-As electrides

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.