Ab Initio Theory of Gate Induced Gaps in Graphene Bilayers

TL;DR

This paper uses ab initio density functional theory to analyze how gate voltages induce energy gaps in graphene bilayers, confirming previous models and exploring screening effects and crystalline inhomogeneity.

Contribution

It provides a detailed ab initio analysis of gate-induced gaps in graphene bilayers, validating and extending phenomenological models with quantitative insights.

Findings

Gate voltage induces a measurable energy gap in graphene bilayers.

Enhanced screening of external potential occurs at small gate voltages.

Crystalline inhomogeneity significantly affects the interlayer potential.

Abstract

We study the gate voltage induced gap that occurs in graphene bilayers using \textit{ab initio} density functional theory. Our calculations confirm the qualitative picture suggested by phenomenological tight-binding and continuum models. We discuss enhanced screening of the external interlayer potential at small gate voltages, which is more pronounced in the \textit{ab initio} calculations, and quantify the role of crystalline inhomogeneity using a tight-binding model self-consistent Hartree calculation.