Armchair graphene nanoribbons: PT-symmetry breaking and exceptional points without dissipation

TL;DR

This paper demonstrates that armchair graphene nanoribbons exhibit PT-symmetry breaking and exceptional points in their transport properties, despite lacking dissipation, by modeling them with an effective non-Hermitian Hamiltonian.

Contribution

It reveals that non-Hermitian physics phenomena like PT-symmetry breaking occur in non-dissipative graphene nanoribbons, expanding understanding of such effects in condensed matter systems.

Findings

Presence of exceptional points in graphene nanoribbons

Observation of PT-symmetry breaking without dissipation

Effective non-Hermitian Hamiltonian describes transport properties

Abstract

We consider a single layer graphene nanoribbon with armchair edges in a longitudinally constant external potential and point out that its transport properties can be described by means of an effective non-Hermitian Hamiltonian. We show that this system has some features typical of dissipative systems, namely the presence of exceptional points and of PT-symmetry breaking, although it is not dissipative.