Boron-based clathrate materials, typically with three-dimensional networks of B atoms, have tunable properties through substitution of guest atoms, but the tuning of B cages themselves has not yet been developed. By combining crystal structural search with the laser-heated diamond anvil cell technique, we successfully synthesized a new B-based clathrate boride, LaB8, at ~108 GPa and ~2100 K. The novel structure has a B-richest cage, with 26 B atoms encapsulating a single La atom. LaB8 demonstrates phonon-mediated superconductivity with an estimated transition temperature of 14 K at ambient pressure, mainly originating from electron-phonon coupling of B cage. This work creates a prototype platform for subsequent investigation on tunable electronic properties through the choice of captured atoms.
@article{arxiv.2109.02313,
title = {Design and Synthesis of Clathrate LaB8 with Superconductivity},
author = {Liang Ma and Xin Yang and Guangtao Liu and Hanyu Liu and Guochun Yang and Hui Wang and Jinqun Cai and Mi Zhou and Hongbo Wang},
journal= {arXiv preprint arXiv:2109.02313},
year = {2021}
}