Quest for high Tc in layered structures: the case of LiB

TL;DR

This study uses electronic structure calculations to evaluate the superconducting potential of LiB, revealing a modest critical temperature and analyzing how doping and pressure affect its superconductivity.

Contribution

It provides the first detailed theoretical analysis of LiB's superconducting properties, comparing it to MgB₂ and exploring ways to enhance its Tc.

Findings

LiB has a Tc of 10-15 K based on calculations.

Electron-phonon coupling in LiB is weaker than in MgB₂.

Doping and pressure are unlikely to significantly increase Tc in LiB.

Abstract

Using electronic structure calculation we study the superconducting properties of the theoretically-devised superconductor MS1-LiB (LiB). We calculate the electron-phonon coupling ($\lambda=0.62$) and the phonon frequency logarithmic average ($<\omega >_{log}=54.6$ meV) and show that the LiB critical temperature is in the range of 10-15 K, despite the frozen-phonon deformation potential being of the same order of MgB$_2$. As a consequence, LiB captures some of the essential physics of MgB$_2$ but (i) the electron-phonon coupling due to $\sigma$ states is smaller and (ii) the precious contribution of the $\pi$ carriers to the critical temperature is lacking. We investigate the possible change in $T_c$ that can be induced by doping and pressure and find that these conditions cannot easily increase $T_c$ in LiB.