Theory of the electronic structure of alternatingMgB2and graphene layered structures

Abstract

Structures for realizing hole-doped $\mathrm{Mg}{\mathrm{B}}_{2}$ without appealing to chemical substitutions are proposed. These structures that consist of alternating $\mathrm{Mg}{\mathrm{B}}_{2}$ and graphene layers have small excess energy compared to bulk graphite and $\mathrm{Mg}{\mathrm{B}}_{2}$. Density functional theory based first-principles electronic structure calculations show significant charge transfer from the $\mathrm{Mg}{\mathrm{B}}_{2}$ layer to graphene, resulting in effectively hole-doped $\mathrm{Mg}{\mathrm{B}}_{2}$ and electron-doped graphene. Substantial enhancement in the density of states at the Fermi level and significant in-plane lattice expansion of the proposed structures are predicted. These structures combines three important factors, namely, hole doping, high density of states at the Fermi level, and in-plane lattice expansion, that are favorable for a strong electron-phonon coupling.