Stability of numerous unexpected actinium hydrides was predicted via evolutionary algorithm USPEX. Electron-phonon interaction was investigated for the hydrogen-richest and most symmetric phases: R3m-AcH10, I4/mmm-AcH12 and P6m2-AcH16. Predicted structures of actinium hydrides are consistent with all previously studied Ac-H phases and demonstrate phonon-mediated high-temperature superconductivity with Tc in the range 204-251 K for R3m-AcH10 at 200 GPa and 199-241 K for P6m2-AcH16 at 150 GPa which was estimated by directly solving of Eliashberg equation. Actinium belongs to the series of d1-elements (Sc-Y-La-Ac) that form high-Tc superconducting (HTSC) hydrides. Combining this observation with p0-HTSC hydrides (MgH6 and CaH6), we propose that p0- and d1-atoms with low-lying empty orbitals tend to form phonon-mediated HTSC metal polyhydrides.
@article{arxiv.1802.05676,
title = {Actinium hydrides $AcH_{10}$, $AcH_{12}$, $AcH_{16}$ as high-temperature conventional superconductors},
author = {Dmitrii V. Semenok and Alexander G. Kvashnin and Ivan A. Kruglov and Artem R. Oganov},
journal= {arXiv preprint arXiv:1802.05676},
year = {2018}
}