Band gap in graphene induced by vacuum fluctuations

TL;DR

This paper predicts that quantum electrodynamics effects, specifically vacuum fluctuations within a microcavity, can induce a measurable band gap in graphene, a phenomenon analogous to the Lamb shift.

Contribution

It introduces a novel theoretical prediction that QED effects can significantly alter graphene's electronic properties by opening a band gap via vacuum fluctuations.

Findings

QED effects can induce a band gap in graphene.

The predicted band gap can surpass the Lamb shift value.

Vacuum fluctuations are responsible for the band gap opening.

Abstract

The electrons in undoped graphene behave as massless Dirac fermions. Therefore graphene can serve as an unique condensed-matter laboratory for the study of various relativistic effects, including quantum electrodynamics (QED) phenomena. Although theoretical models describing electronic properties of graphene have been elaborated in details, the QED effects were usually neglected. In this paper we demonstrate theoretically that QED can drastically modify electronic properties of graphene. We predict the following QED effect - the opening of the band gap in a graphene monolayer placed inside a planar microcavity filled with an optically active media. We show that this phenomenon occurs due to the vacuum fluctuations of the electromagnetic field and is similar to such a well-known phenomenon as a vacuum-induced splitting of atomic levels (the Lamb shift). We estimate the characteristic value of the band gap and find that it can sufficiently exceed the value of the Lamb shift.