Electric Field Tunable Band Gap in Commensurate Twisted Bilayer Graphene

Fuente: arXiv
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Autores principales: Talkington, Spenser, Mele, Eugene J.
Formato: Preprint
Publicado: 2022
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author Talkington, Spenser
Mele, Eugene J.
author_facet Talkington, Spenser
Mele, Eugene J.
contents Bernal bilayer graphene exhibits a band gap that is tunable through the infrared with an electric field. We show that sublattice odd commensurate twisted bilayer graphene (C-TBG) exhibits a band gap that is tunable through the terahertz with an electric field. We show that from the perspective of terahertz optics the sublattice odd and even forms of C-TBG are "inflated" versions of Bernal and AA stacked bilayer graphene respectively with energy scales reduced by a factor of 110 for the 21.79 degree commensurate unit cell. This lower energy scale is accompanied by a correspondingly smaller gate voltage, which means that the strong-field regime is more easily accessible than in the Bernal case. Finally, we show that the interlayer coherence energy is a directly accessible experimental quantity through the position of a power-law divergence in the optical conductivity.
format Preprint
id arxiv_https___arxiv_org_abs_2212_00549
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Electric Field Tunable Band Gap in Commensurate Twisted Bilayer Graphene
Talkington, Spenser
Mele, Eugene J.
Mesoscale and Nanoscale Physics
Bernal bilayer graphene exhibits a band gap that is tunable through the infrared with an electric field. We show that sublattice odd commensurate twisted bilayer graphene (C-TBG) exhibits a band gap that is tunable through the terahertz with an electric field. We show that from the perspective of terahertz optics the sublattice odd and even forms of C-TBG are "inflated" versions of Bernal and AA stacked bilayer graphene respectively with energy scales reduced by a factor of 110 for the 21.79 degree commensurate unit cell. This lower energy scale is accompanied by a correspondingly smaller gate voltage, which means that the strong-field regime is more easily accessible than in the Bernal case. Finally, we show that the interlayer coherence energy is a directly accessible experimental quantity through the position of a power-law divergence in the optical conductivity.
title Electric Field Tunable Band Gap in Commensurate Twisted Bilayer Graphene
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2212.00549