Superconducting Electride LiS with a Transition Temperature above the McMillan Limit.

An electride, characterized by unique interstitial anionic electrons (IAEs), offers promising avenues for modulating its superconductivity. The pressure-dependent coupling between IAEs and orbital electrons significantly affects the superconducting transition temperature (). However, existing research has predominantly concentrated on pressures within 300 GPa. To advance the understanding, we propose investigating the Li-S system under ultrahigh pressure to unveil novel electride superconductors. Five stable Li-rich electrides with diverse IAE topologies, including one LiS, three LiS, and one LiS phases, are identified through structural search calculations. Among the LiS phases, in the 2/ phase (600 GPa), the IAEs are connected to the S atomic extra-nuclear electrons with the unconventional orbital attribute due to the extreme pressure, while two low-pressure -3 (25 GPa) and 2/ (400 GPa) phases have interconnected IAEs. Due to its unique IAE attributes, 2/ LiS exhibits the highest of 53.29 K at 600 GPa. Its superconductivity results from the coupling of the S , Li electrons, and IAEs with the low-frequency phonons associated with the attraction between IAEs and the Li-S framework. Our work enhances insights into IAEs within electrides and their role in facilitating superconductivity.