Two-gap-like anisotropic superconductivity in a bulk boron kagome lattice

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• Superconductivity in elemental boron has been primarily observed under high pressure.
• Discovering ambient-pressure superconductivity in boron allotropes remains a significant challenge.
• Previous theoretical and experimental studies have yielded limited results for bulk boron at normal pressure.

Purpose of the Study:

• To propose and investigate a novel metastable metallic boron phase.
• To demonstrate the potential for high-temperature superconductivity in this phase at ambient pressure.
• To elucidate the underlying mechanisms responsible for the predicted superconductivity.

Main Methods:

• First-principles calculations were employed to model the electronic and vibrational properties of the proposed boron phase.
• Analysis of electron-phonon coupling and Fermi surface characteristics.
• Investigation of phonon modes and their relation to charge density wave instabilities.

Main Results:

• A dynamically stable, metastable metallic boron phase within a kagome lattice structure was identified.
• High superconducting critical temperature (Tc) of approximately 34-39 K was predicted at ambient pressure.
• Strong electron-phonon coupling, attributed to specific covalent bonding and Fermi surface features, was found to drive superconductivity.
• A two-gap-like superconducting nature was indicated, linked to distinct covalent bonding types.

Conclusions:

• The proposed boron kagome phase offers a promising candidate for elemental, ambient-pressure, high-temperature superconductivity.
• The findings highlight the role of specific phonon modes and electronic structure in achieving high Tc.
• This work provides a theoretical foundation for experimental exploration of this novel superconducting material.