Theoretical Insights into High-T _c Superconductivity of Structurally Ordered YThH₁₈: A First-Principles Study

Area of Science:

• Materials Science
• Condensed Matter Physics
• Chemistry

Background:

• Growing interest in high-temperature superconductors for energy and transportation.
• Ternary superhydrides, containing hydrogen and two other elements, are a promising research area.

Purpose of the Study:

• To search for Y-Th-H ternary compounds.
• To investigate the structural ordering of Th-doped YH9 and its alloyed structures.
• To explore potential high-temperature superconductivity in novel multinary hydrides.

Main Methods:

• Evolutionary search methodology.
• Electron-phonon calculations.
• Analysis of alloyed structure formation.

Main Results:

• Identification of a stable ternary superhydride, P6̅m2-YThH18.
• Predicted critical temperature (Tc) of 222 K at 200 GPa.
• Confirmation of P6̅m2-YThH18 as a structurally ordered phase derived from disordered Th-doped YH9.

Conclusions:

• The discovery of P6̅m2-YThH18 opens new avenues for multinary superhydride research.
• This ordered structure may facilitate experimental synthesis.
• The findings have significant implications for advancing high-temperature superconductivity.