Ab initiostudy of superconducting hexagonalBe2Liunder pressure

Abstract

Following the recent interest on lithium alloys under pressure, we present first-principles calculations of the electronic band structure and lattice dynamics for the ${\text{MgB}}_{2}$-like layered ${\text{Be}}_{2}\text{Li}$ at 80 GPa. Under pressure, the increasing electronic localization reduces the effective dimensionality of ${\text{Be}}_{2}\text{Li}$, showing both two-dimensional and one-dimensional conducting electronic channels. The numerical results reveal the presence of an ultrasoft strongly anharmonic ${B}_{2g}$ phonon mode associated to the atomic buckling in the layers, which shows a high electron-phonon interaction near the zone center and (besides the moderately coupled ${E}_{2g}$ in-plane and ${A}_{1g}$ interlayer Be modes) is responsible for a predicted superconducting transition around 2.5 K.