Electronic confinement in quantum dots of twisted bilayer graphene
arXiv:2110.10823 · doi:10.1103/PhysRevB.104.235417
Abstract
Electronic properties of quantum dots (QDs) depend sensitively on their parent materials. Therefore, confined electronic states in graphene QDs (GQDs) of monolayer and Bernal-stacked bilayer graphene are quite different. Twisted bilayer graphene (TBG) is distinct from monolayer and Bernal-stacked bilayer graphene because of the new degree of freedom: twist angle. In the past few years, numerous efforts have been made to realize the GQDs of monolayer and Bernal-stacked bilayer graphene and achieved great success. Thus far, however, strategies for realizing GQDs of TBG have been elusive. Here, we demonstrate a general approach for fabricating stationary GQDs of TBG by introducing nanoscale p-n junctions with sharp boundaries in the TBG. We verify the confinement of low-energy massless Dirac fermions via whispering-gallery modes in the GQDs of TBG. Unexpectedly, electronic states around van Hove singularities of the TBG are also strongly modified around the GQDs. Such a feature has never been reported and is attributed to spatial variation of the interlayer coupling in the TBG induced by the GQDs.
References in corpus (28)
- Chiral tunneling and the Klein paradox in graphene
- Graphene bilayer with a twist: electronic structure
- Observation of Van Hove singularities in twisted graphene layers
- Graphene Bilayers with a Twist
- Evidence of Klein tunneling in graphene p-n junctions
- Continuum Model of the Twisted Bilayer
- Unravelling the intrinsic and robust nature of van Hove singularities in twisted bilayer graphene
- Imaging electrostatically confined Dirac fermions in graphene quantum dots
- Creating and Probing Electron Whispering Gallery Modes in Graphene
- Gate Defined Quantum Confinement in Suspended Bilayer Graphene
- An On/Off Berry Phase Switch in Circular Graphene Resonators
- Electrostatically confined monolayer graphene quantum dots with orbital and valley splittings
- Valley Polarization and Inversion in Strained Graphene via Pseudo-Landau Levels, Valley Splitting of Real Landau Levels and Confined States
- Tuning a Circular p-n Junction in Graphene from Quantum Confinement to Optical Guiding
- Gate defined zero- and one-dimensional confinement in bilayer graphene
- Chiral Tunnelling in Twisted Graphene Bilayer
- Large tunable valley splitting in edge-free graphene quantum dots on boron nitride
- Nanoscale control of rewriteable doping patterns in pristine graphene/boron nitride heterostructures
- Interaction Driven Quantum Hall Wedding cake-like Structures in Graphene Quantum Dots
- Generating nanoscale and atomically-sharp p-n junctions in graphene via monolayer-vacancy-island engineering of Cu surface
- Electron-electron interactions in bilayer graphene quantum dots
- Twistronics in graphene-based van der Waals structures
- Visualization and Manipulation of Bilayer Graphene Quantum Dots with Broken Rotational Symmetry and Nontrivial Topology
- Massless Dirac Fermions Trapping in a Quasi-one-dimensional npn Junction of a Continuous Graphene Monolayer
- Relativistic Artificial Molecules Realized by Two Coupled Graphene Quantum Dots
- Breaking whispering-gallery modes of massless Dirac fermions in graphene quantum dots by Coulomb interaction
- A Movable Valley Switch Driven by Berry Phase in Bilayer Graphene Resonators
- Spatial Confinement, Magnetic Localization and Their Interactions on Massless Dirac Fermions