The electronic and optical properties of graphene nanoribbons under the influence of the periodic strain

TL;DR

This study investigates how uniaxial periodic strain affects the electronic and optical properties of graphene nanoribbons, revealing modifications in band structure, optical transitions, and selection rules through theoretical analysis.

Contribution

It provides a detailed theoretical analysis of the effects of periodic strain on GNRs, including the emergence of miniband gaps and altered optical selection rules, with rigorous proof of wavefunction parity.

Findings

Momentum-resolved gaps within minibands emerge under strain.

Optical transition rules are altered due to wavefunction parity changes.

Absorption spectra are influenced by velocity matrix elements and joint density of states.

Abstract

The electronic and optical properties of graphene nanoribbons under uniaxial periodic strain have been explored using various nearest-neighbor hopping patterns. It is found that by properly selecting hopping patterns, momentum-resolved gaps within minibands emerge, modifying the energy band structure to exhibit hollowed-out profiles, and enhancing peak intensity in local density of states but reducing peak count. The optical transitions are impacted by altered parity symmetry of wavefunctions, causing changes in optical selection rules. The parity of wavefunctions for strained GNRs has been established through rigorous mathematical proof, whereby the optical selection rule is determined for the strained GNRs. The absorption curves arise from a complex interplay between diminished velocity matrix elements and escalated joint density of states.