A many-body overview of low-energy optical excitations in armchair graphene nanoribbons

TL;DR

This paper provides a comprehensive many-body analysis of low-energy optical excitations in armchair graphene nanoribbons, revealing detailed excitonic spectra and polarization-dependent optical properties through exact diagonalization of the Hubbard model.

Contribution

It offers the first complete survey of low-energy optical excitations in AGNRs considering both polarizations using a full many-body approach.

Findings

One-photon eigenstates are well separated in energy.

Both eigenstates couple to the same two-photon states.

Optical features are observable in polarized absorption measurements.

Abstract

Excitonic spectra of armchair graphene nanoribbons (AGNRs) obtained from a full many-body exact diagonalization of the Hubbard model are reported for both longitudinally and transversely polarized photons, thus providing a complete survey of low-energy may-body optical excitations in these systems. The resulting one-photon allowed eigenstates turn out to be well separated in energy from each other but both couple to the same set of two-photon allowed states. The magnitude of the calculated optical oscillator strengths for perpendicular polarization suggest that these optical features can be indeed observed in polarized absorption measurements.