Superconductive electride Li10⁢Bi under high pressure

Abstract

<p>Electride superconductors with unique interstitial anionic electrons (IAEs) have recently attracted considerable attention. Lithium-based electride superconductors are of particular interest because of their striking electride states and superconductivity. Electrides containing Li and Bi are not yet known despite the previously reported Li-Bi binary compounds. In this study, we systematically simulated Li-rich bismuthides under compression using a state-of-the-art structure search approach combined with first-principles calculations. Strikingly, several unforeseen stable electride phases with high lithium coordination, diverse distributions of IAEs, and metallic characteristics were identified, that is, Li5⁢Bi, Li7⁢Bi, Li8⁢Bi, Li9⁢Bi, and Li10⁢Bi, where continuous phase transitions from orthorhombic <em>Pmmn</em> to <em>Cmcm</em> were observed in Li5⁢Bi, accompanied by a transformation from two-dimensional to zero-dimensional IAEs. Furthermore, superconducting property calculations revealed that Li10⁢Bi, featuring one-dimensional zigzag-like IAEs, had a superconducting transition temperature (𝑇𝑐) of 4.5 K at a moderate pressure of 50 GPa, making it the highest lithium concentration electride superconductor consisting of Li and nitrogen group elements. The strong coupling between the electron states of Li 2⁢𝑝 and the IAEs and Li-associated phonon modes dominates the remarkable superconductivity of Li10⁢Bi. This study offers valuable insights into emerging lithium-bearing electride superconductors.<br></p>