Search for high Tc in layered structures: The case of LiB

Using electronic structure calculation we study the superconducting properties of the theoretically devised superconductor MS1-LiB (LiB). We calculate the electron-phonon coupling (λ=0.62) and the phonon frequency logarithmic average (ω 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 Mg B2. As a consequence, LiB captures some of the essential physics of Mg B2 but (i) the electron-phonon coupling due to σ states is smaller and (ii) the precious contribution of the π carriers to the critical temperature is lacking. We investigate the possible change in Tc that can be induced by doping and pressure and find that these conditions cannot easily increase Tc in LiB. © 2007 The American Physical Society.