Superconducting H₇ chain in gallium hydrides at high pressure

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Chemistry

Background:

• High-pressure hydrides are promising candidates for high-temperature (Tc) superconductors.
• Exploring novel hydride structures is crucial for advancing superconductivity research.

Purpose of the Study:

• To systematically investigate the crystal structures and superconducting properties of gallium hydrides.
• To identify new thermodynamically stable gallium hydride phases under high pressure.

Main Methods:

• Utilized an advanced structure-search method combined with first-principles calculations.
• Analyzed crystal structures, thermodynamic stability, and superconducting properties of gallium hydrides.

Main Results:

• Identified an unconventional stoichiometric GaH7 gallium hydride, stable above 247 GPa.
• Observed a unique H7 chain structure intercalating the Ga framework.
• Calculated a high estimated Tc above 100 K for GaH7 at 200-300 GPa.

Conclusions:

• GaH7 exhibits strong electron-phonon coupling, contributing to its high Tc.
• This finding provides a novel example of superconducting hydrogen motifs under high pressure.
• The results may inspire further experimental synthesis and exploration of similar materials.