Predicted hot superconductivity in LaSc₂H₂₄ under pressure.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Recent discoveries of clathrate hydrides (e.g., CaH6, YH6, YH9, LaH10) show superconductivity above 200 K under pressure.
• Ternary hydrides offer greater material diversity and structural configurations for exploring high-temperature superconductivity.

Purpose of the Study:

• To computationally search for novel, thermodynamically stable ternary clathrate hydride structures.
• To predict the superconducting properties of these newly identified hydride phases.

Main Methods:

• Extensive computational searches were employed to identify stable clathrate hydride structures.
• The Bardeen-Cooper-Schrieffer (BCS) theory was used to calculate superconducting critical temperatures (Tc).
• The effects of anharmonicity were included in the calculations for accurate Tc predictions.

Main Results:

• Prediction of a unique class of thermodynamically stable clathrate hydrides with novel H24 and H30 hydrogen cages at megabar pressures.
• LaSc2H24 identified as a promising candidate for high-temperature superconductivity, with calculated Tc up to 331 K at 250 GPa.
• High critical temperatures attributed to a large hydrogen-derived density of states at the Fermi level, influenced by the novel H24 and H30 cages.

Conclusions:

• The introduction of Scandium (Sc) into the Lanthanum-Hydrogen (La-H) system facilitates the discovery of new ternary clathrate superhydrides.
• These findings are expected to guide the future design and experimental realization of room-temperature superconductors.