Superconductivity in Room Temperature Stable electride and high-pressure phases of alkali metals

TL;DR

This paper reveals that the room temperature stable electride C12A7:e- exhibits superconductivity at ambient pressure, with its electronic structure closely resembling high-pressure phases of alkali metals, and identifies the electronic transition responsible for superconductivity.

Contribution

It demonstrates that the electronic structure of C12A7:e- is similar to high-pressure alkali metal phases and links superconductivity to an s- to sd-hybridization transition at the Fermi level.

Findings

C12A7:e- exhibits superconductivity at 0.2-0.4K at ambient pressure.

Electronic structure of C12A7:e- resembles high-pressure alkali metal phases.

Superconductivity is associated with a transition from s- to sd-hybridized states at the Fermi energy.

Abstract

S-band metals such as alkali and alkaline earth metals do not undergo a superconducting transition (SCT) at an ambient pressure, but their high-pressure phases do. In contrast, room temperature stable electride electride (C12A7:e-) in which anionic electrons in the crystallographic sub-nanometer-size cages have high s-character exhibits SCT at 0.2-0.4K at an ambient pressure. In this paper we report that crystal and electronic structure of C12A7:e- are close to those of the high pressure superconducting phase of alkali and alkaline earth metals and the SCT of both materials is induced when electron nature at Fermi energy (EF) switches from s- to sd-hybridized state.