We report the observation of superconductivity in cubic La3Al single crystal. It shows a metallic behavior at a normal state without observable structural transition and enters the superconducting state below Tc ~ 6.32 K. Detailed characterizations and analysis indicate that cubic La3Al is a bulk type-II BCS superconductor. Moreover, theoretical calculations show that it can host interstitial anionic electrons, which are located at the body center of cubic unit cell, and confirm the electron-phonon coupling as the superconducting mechamism. Thus, cubic La3Al can be regarded as an novel electride superconductor.
@article{arxiv.2509.22559,
title = {Superconductivity in cubic La3Al with interstitial anionic electrons},
author = {Zhijun Tu and Peihan Sun and Donghan Jia and Huiyang Gou and Kai Liu and Hechang Lei},
journal= {arXiv preprint arXiv:2509.22559},
year = {2025}
}