Stress-induced high-T superconductivity in solid molecular hydrogen.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• Solid molecular hydrogen is theoretically predicted to exhibit metallicity and high-temperature superconductivity under extreme hydrostatic pressures.
• The effects of nonhydrostatic conditions, including anisotropic stresses, on the electronic properties of dense hydrogen remain largely unknown.

Purpose of the Study:

• To investigate the influence of anisotropic stresses on the electronic properties and superconductivity of solid molecular hydrogen at multimegabar pressures.
• To explore a novel mechanism for enhancing superconductivity in dense hydrogen beyond purely hydrostatic compression.

Main Methods:

• First-principles calculations were employed to simulate solid molecular hydrogen under extreme pressures.
• The study focused on analyzing the impact of anisotropic compressive and shear stresses on crystal symmetry and charge distribution.

Main Results:

• Anisotropic stresses can induce significant crystal symmetry reduction and charge redistribution in solid molecular hydrogen.
• These changes accelerate bandgap closure, promoting superconductivity compared to hydrostatic compression.
• The findings suggest that nonhydrostatic conditions can be leveraged to enhance superconductivity.

Conclusions:

• Nonhydrostatic conditions present a viable and largely unexplored mechanism for achieving enhanced superconductivity in dense hydrogen.
• The results have implications for designing superconducting hydrogen-rich compounds and understanding phenomena in other molecular crystals.