Electronic and optical properties of LiBC

TL;DR

This study investigates the electronic and optical properties of LiBC, a light-element semiconducting borocarbide, revealing phonon modes and potential for high-temperature superconductivity due to strong electron-phonon coupling.

Contribution

The paper provides experimental characterization of LiBC's phonon spectrum and optical properties, supporting its potential for high-temperature superconductivity.

Findings

In-plane B-C stretching mode at 150 meV detected

Strong electron-phonon coupling observed in LiBC

Potential for high-temperature superconductivity in hole-doped LiBC

Abstract

LiBC, a semiconducting ternary borocarbide constituted of the lightest elements only, has been synthesized and characterized by x-ray powder diffraction, dielectric spectroscopy, and conductivity measurements. Utilizing an infrared microscope the phonon spectrum has been investigated in single crystals. The in-plane B-C stretching mode has been detected at 150 meV, noticeably higher than in AlB2, a non-superconducting isostructural analog of MgB2. It is this stretching mode, which reveals a strong electron-phonon coupling in MgB2, driving it into a superconducting state below 40 K, and is believed to mediate predicted high-temperature superconductivity in hole-doped LiBC [H. Rosner, A. Kitaigorodsky, and W. E. Pickett, Phys. Rev. Lett. 88, 127001 (2002)].