Superconducting Li10Se electride under pressure.

Abstract

Achieving a compound with interesting multiple coexisting states, such as electride, metallicity, and superconductivity, is of great interest in basic research and practical application. Pressure has become an effective way to realize high-temperature superconductivity in hydrides, whereas most electrides are semiconducting or insulating at high pressure. Here, we have applied swarm-intelligence structural search to identify a hitherto unknown C2/m Li10Se electride that is superconducting at high pressure. More interestingly, Li10Se is estimated to exhibit the highest Tc value of 16K at 50GPa, which is the lowest pressure among Li-based chalcogen electrides. This superconducting transition is dominated by Se-related low frequency vibration modes. The increasing electronic occupation of the Se 4d orbital and the decreasing amount of interstitial anion electrons with pressure heighten their coupling with low-frequency phonons, which is responsible for the enhancement of the Tc value. The finding of Li-based chalcogen superconducting electrides provides a reference for the realization of other superconducting electrides at lower pressures.