Pressure-induced high-temperature superconductivity in ternary Y-Zr-H compounds.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Compressed hydrogen-rich compounds are promising candidates for high-temperature superconductors.
• Ternary hydrides offer potential for enhanced superconducting properties compared to binary systems.

Purpose of the Study:

• To systematically investigate the Y-Zr-H ternary hydride system under pressure.
• To identify novel stable and metastable hydrides with potential superconducting properties.
• To understand the factors influencing superconductivity in these ternary hydrides.

Main Methods:

• Computational investigation of Y-Zr-H ternary hydrides under high pressure.
• Electron-phonon coupling calculations to predict superconducting properties.
• Analysis of structural stability and electronic structure.

Main Results:

• Discovery of stable hydrides: YZrH6, YZrH8, YZr3H16, YZrH18, and metastable clathrate hexahydrides.
• All identified hydrides exhibit high-temperature superconductivity, outperforming binary Zr-H systems.
• YZrH6 shows dynamic stability at ambient pressure with a critical temperature (Tc) of 16 K.
• Stable YZrH18 and metastable Y3ZrH24 demonstrate high Tc of 156 K and 185 K at 200 GPa.
• Phonon modes involving H atoms significantly contribute to electron-phonon coupling.

Conclusions:

• Hydrogen content and Y/Zr stoichiometry critically influence the density of states at the Fermi level and superconductivity.
• This study represents a significant advancement in understanding superconductivity and stability in transition metal ternary hydrides.
• The identified hydrides offer promising avenues for future research in high-temperature superconductivity.