Chiral Symmetry and Many-Body Effect in Multilayer Graphene

TL;DR

This paper explores how chiral symmetry affects many-body interactions in multilayer graphene under magnetic fields, revealing a degenerate ground state and layer-dependent energy gaps.

Contribution

It demonstrates that chiral symmetry leads to a doubly-degenerate ground state in multilayer graphene regardless of layer number and quantifies the gap reduction with increasing layers.

Findings

Ground state is a doubly-degenerate chiral condensate

Many-body gap decreases monotonically with layers

Results obtained via exact diagonalization

Abstract

Influence of the chiral symmetry on the many-body problem in multilayer graphene in magnetic fields is investigated. For a spinless electron model on the honeycomb lattice the many-body ground state is shown to be a doubly-degenerate chiral condensate irrespective of the number of layers. The energy spectrum calculated numerically with the exact diagonalization method reveals for ABC-stacked multilayer graphenes that the many-body gap decreases monotonically with the number of layers.