Superconducting Li₁₁Sb₂ electride at ambient pressure

The exploration of electrides, especially stabilized at ambient pressure, is of great interest in condensed matter physics due to their intriguing properties induced by interstitial anionic electrons (IAEs). Herein, on the basis of first-principles calculations, we have proposed a novel metastable Li11Sb2 electride, dubbed as C2/m-II phase, which is quenched from pressurized Li11Sb2 with a C2/m-I symmetry through an in-plane Li-4 ring rotation mediated by IAEs. The stability of the C2/m-II phase can be attributed to the redistribution of IAEs and reduction of internal energy generated by depressurization. Interestingly, the C2/m-II phase is predicted to possess unexpected superconductivity and an anisotropic work function. The IAE-induced Fermi surface nesting and the resultant acoustic phonon softening play a critical role in the superconductivity. Our study might provide an alternative way to prepare metastable electrides with interesting properties.