Strongly bound excitons dominate electronic relaxation in resonantly excited twisted bilayer graphene

  title={Strongly bound excitons dominate electronic relaxation in resonantly excited twisted bilayer graphene},
  author={Hiral Patel and Lola Brown and Yufeng Liang and Li Yang and Jiwoong Park and Matt W. Graham},
When two sheets of graphene stack in a twisted bilayer graphene (tBLG) configuration, the resulting constrained overlap between interplanar 2p orbitals produce angle-tunable electronic absorption resonances. Using a novel combination of multiphoton transient absorption (TA) microscopy and TEM, we resolve the resonant electronic structure, and ensuing electronic relaxation inside single tBLG domains. Strikingly, we find that the transient electronic population in resonantly excited tBLG domains… 
24 Citations

Figures from this paper

Stacking angle-tunable photoluminescence from interlayer exciton states in twisted bilayer graphene
Photoluminescence emission from tBLG after resonant 2-photon excitation is reported and hybrid metal-exciton behavior electron thermalization and PL emission are tunable with stacking angle for potential enhancements in optoelectronic and fast-photosensing graphene-based applications.
Probing the bright exciton state in twisted bilayer graphene via resonant Raman scattering
The band structure of bilayer graphene is tunable by introducing a relative twist angle between the two layers, unlocking exotic phases, such as superconductor and Mott insulator, and providing a
Angle-tunable intersubband photoabsorption and enhanced photobleaching in twisted bilayer graphene
Van der Waals heterostructures obtained by artificially stacking two-dimensional crystals represent the frontier of material engineering, demonstrating properties superior to those of the starting
Tunable Second Harmonic Generation in Twisted Bilayer Graphene
Summary Twisted stacking of van der Waals materials introduces a new way in band-structure engineering and has given rise to numerous extraordinary physical phenomena. Despite the absence of second
Opto-electronic properties of twisted bilayer graphene quantum dots
Abstract The electronic and interband optical properties of vertically coupled stacked graphene quantum dots are investigated using the tight-binding method. Both zigzag and armchair edge
Excitonic effects in twisted bilayer graphene
Abstract In the present work, we consider the excitonic effects in the twisted bilayer graphene (tBLG) within the rotated bilayer Hubbard model. Both, intralayer and interlayer Coulomb interactions
Ultraflatbands and Shear Solitons in Moiré Patterns of Twisted Bilayer Transition Metal Dichalcogenides.
Using first-principles density functional theory calculations, the emergence of ultraflatbands at the valence band edge in twisted bilayer MoS_{2}, a prototypical transition metal dichalcogenide, is shown.
Kohn-Luttinger Superconductivity in Twisted Bilayer Graphene.
We show that the recently observed superconductivity in twisted bilayer graphene (TBG) can be explained as a consequence of the Kohn-Luttinger (KL) instability which leads to an effective attraction
Linear response of twisted bilayer graphene: Continuum versus tight-binding models
We present a linear response calculation for twisted bilayer graphene. The calculation is performed for both the continuum and tight-binding models, with the aim of assessing the validity of the
Strong mid-infrared photoresponse in small-twist-angle bilayer graphene
Small-twist-angle (<2°) bilayer graphene has received extraordinary attention recently due to its exciting physical properties 1 – 11 . Compared with monolayer graphene, the Brillouin zone folding in