Hydrides hold promise as high-temperature superconductors under high pressures. Recent theoretical or experimental hydride structures on achieving high-pressure superconductivity are composed mainly of hydrogen fragments. Through a systematic investigation of scandium hydrides with different hydrogen contents using the particle swarm optimization method (PSO) and the evolutionary algorithm (GA), we have predicted four new scandium hydrides (ScH6, ScH9, ScH10 and ScH12), which are stable above 150 GPa. Several interesting types of hydrogen species with increased H contents were found. For example, H atoms form “H5” pentagons or “H8” octagons in ScH9, ScH10 and ScH12. Electron-phonon calculations revealed the superconductive potential of ScH6, ScH9, ScH10 and ScH12 with estimated transition temperatures (Tc) of 120-163 K above 250 GPa. These hydrides are predicted to be synthesized by compressing the mixture of ScH3 and H2 above 150 GPa. The encouraging results stimulated further experimental and theoretical studies on high superconducting heavy-element hydrides at high pressures.

Superconductivity in scandium hydrides under pressure

254th National Meeting (2017)

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