Electronic and optical properties of graphene nanoribbons in external fields

TL;DR

This review comprehensively discusses the electronic and optical properties of graphene nanoribbons under various external fields, highlighting complex phenomena due to geometric and field interactions, with theoretical predictions validated by experiments.

Contribution

It provides a detailed synthesis of how external fields and structural factors influence graphene nanoribbons' properties, including new insights into Landau levels and optical spectra.

Findings

Complex electronic structures induced by external fields.

Diverse absorption spectra with unique selection rules.

Experimental validation of theoretical predictions.

Abstract

A review work is done for electronic and optical properties of graphene nanoribbons in magnetic, electric, composite, and modulated fields. Effects due to the lateral confinement, curvature, stacking, non-uniform subsystems and hybrid structures are taken into account. The special electronic properties, induced by complex competitions between external fields and geometric structures, include many one-dimensional parabolic subbands, standing waves, peculiar edge-localized states, width- and field-dependent energy gaps, magnetic-quantized quasi-Landau levels, curvature-induced oscillating Landau subbands, crossings and anti-crossings of quasi-Landau levels, coexistence and combination of energy spectra in layered structures, and various peak structures in the density of states. There exist diverse absorption spectra and different selection rules, covering edge-dependent selection rules, magneto-optical selection rule, splitting of the Landau absorption peaks, intragroup and intergroup Landau transitions, as well as coexistence of monolayer-like and bilayer-like Landau absorption spectra. Detailed comparisons are made between the theoretical calculations and experimental measurements. The predicted results, the parabolic subbands, edge-localized states, gap opening and modulation, and spatial distribution of Landau subbands, have been verified by various experimental measurements.