Tunable Excitons in Rhombohedral Trilayer Graphene

Abstract

Trilayer graphene is receiving an increasing level of attention due to its stacking--dependent magnetoelectric and optoelectric properties, and its more robust ferromagnetism relative to monolayer and bilayer variants. Additionally, rhombohedral stacked trilayer graphene presents the possibility of easily opening a gap via either an external electric field perpendicular to the layers, or via the application of external strain. In this paper, we consider an external electric field to open a bandgap in rhombohedral trilayer graphene and study the excitonic optical response of the system. This is done via the combination of a tight binding model with the Bethe--Salpeter equation, solved semi--analytically and requiring only a simple numerical quadrature. We then discuss the valley--dependent optical selection rules, followed by the computation of the excitonic linear optical conductivity for the case of a rhombohedral graphene trilayer encapsulated in hexagonal boron nitride. The tunability of the excitonic resonances via an external field is also discussed, together with the increasing localization of the excitonic states as the field increases.

17 pages, 6 figures

References in corpus (10)

• Electric Field Effect in Atomically Thin Carbon Films
• Band Structure of ABC-Stacked Graphene Trilayers
• Ultrafast transition between exciton phases in van der Waals heterostructures
• Tunable Excitons in Biased Bilayer Graphene
• Nonlinear optical selection rules of excitons in monolayer transition metal dichalcogenides
• Ferromagnetism in ABC-trilayer graphene
• Optical response and band structure of LiCoO2 including electron-hole interaction effects
• Absorption and optical selection rules of tunable excitons in biased bilayer graphene
• Exciton absorption, band structure, and optical emission in biased bilayer graphene
• A perturbative approach to the polaron shift of excitons in transition metal dichalcogeniedes

Cited by in corpus (7)

• Electrically Tunable Interband Collective Excitations in Biased Bilayer and Trilayer Graphene
• Anisotropic linear and non-linear excitonic optical properties of buckled monolayer semiconductors
• Dynamical screening and excitonic bound states in biased bilayer graphene
• Tunable nonlinear excitonic optical response in biased bilayer graphene
• Identification of graphite with perfect rhombohedral stacking by electronic Raman scattering
• The Transmission Line Model for 2D Materials and van der Waals Heterostructures
• Strongly Coupled Exciton--Hyperbolic-phonon-polariton Hybridized States in hBN-encapsulated Biased Bilayer Graphene