Electron-hole Hybridization in Bilayer Graphene

TL;DR

This paper reports the discovery of electron-hole hybridization in bilayer graphene under periodic potentials, revealing local band gaps and flat bands, with implications for topological quantum computation.

Contribution

It demonstrates for the first time the hybridization of electron and hole sub-bands in bilayer graphene, enabling tunable flat bands and potential Majorana modes.

Findings

Hybridization of electron and hole sub-bands observed

Formation of local band gaps at charge neutrality points

Emergence of flat bands suitable for correlated effects

Abstract

Band structure determines the motion of electrons in a solid, giving rise to exotic phenomena when properly engineered. Drawing an analogy between electrons and photons, artificially designed optical lattices indicate the possibility of a similar band modulation effect in graphene systems. Yet due to the fermionic nature of electrons, modulated electronic systems promise far richer categories of behaviors than those found in optical lattices. Here, we uncovered a strong modulation of electronic states in bilayer graphene subject to periodic potentials. We observed for the first time the hybridization of electron and hole sub-bands, resulting in local band gaps at both primary and secondary charge neutrality points. Such hybridization leads to the formation of flat bands, enabling the study of correlated effects in graphene systems. This work may also offer a viable platform to form and continuously tune Majorana zero modes, which is important to the realization of topological quantum computation.