Exciton states in a circular graphene quantum dot: magnetic field induced intravalley to intervalley transition
arXiv:1612.08031 · doi:10.1103/PhysRevB.95.045409
Abstract
The magnetic-field dependence of the energy spectrum, wave function, binding energy and oscillator strength of exciton states confined in a circular graphene quantum dot (CGQD) are obtained within the configuration interaction (CI) method. We predict that: (1) excitonic effects are very significant in the CGQD as a consequence of a combination of geometric confinement, magnetic confinement and reduced screening; (2) two types of excitons (intravalley and intervalley excitons) are present in the CGQD because of the valley degree of freedom in graphene; (3) the intravalley and intervalley exciton states display different magnetic-field dependencies due to the different electron-hole symmetries of the single-particle energy spectra; (4) with increasing magnetic field, the exciton ground state in the CGQD undergoes an intravalley to intervalley transition accompanied by a change of angular momentum; (5) the exciton binding energy does not increase monotonically with the magnetic field due to the competition between geometric and magnetic confinements; and (6) the optical transitions of the intervalley and intravalley excitons can be tuned by the magnetic field and valley-dependent excitonic transitions can be realized in CGQD.
arXiv comment10 pages, 8 figures, to appear in Phys. Rev. B
References in corpus (38)
- Electric Field Effect in Atomically Thin Carbon Films
- The electronic properties of graphene
- Two-Dimensional Gas of Massless Dirac Fermions in Graphene
- Experimental Observation of Quantum Hall Effect and Berry's Phase in Graphene
- Graphene Photonics and Optoelectronics
- Energy Band Gap Engineering of Graphene Nanoribbons
- Chiral tunneling and the Klein paradox in graphene
- Electronic transport in two dimensional graphene
- Chaotic Dirac billiard in graphene quantum dots
- Dielectric function, screening, and plasmons in 2D graphene
- Graphene Nano-Ribbon Electronics
- Electron-Electron Interactions in Graphene: Current Status and Perspectives
- Properties of Graphene: A Theoretical Perspective
- Theory of Neutral and Charged Excitons in Monolayer Transition Metal Dichalcogenides
- Excitonic Effects on the Optical Response of Graphene and Bilayer Graphene
- Seeing many-body effects in single- and few-layer graphene: Observation of two-dimensional saddle-point excitons
- Tuning of energy levels and optical properties of graphene quantum dots
- Electronic properties of mesoscopic graphene structures: charge confinement and control of spin and charge transport
- Tunable Coulomb blockade in nanostructured graphene
- Graphene quantum dots: Beyond a Dirac billiard
- Energy levels of triangular and hexagonal graphene quantum dots: a comparative study between the tight-binding and the Dirac approach
- Quantum dots and spin qubits in graphene
- Analytic Model for the Energy Spectrum of a Graphene Quantum Dot in a Perpendicular Magnetic Field
- Electron-Hole Crossover in Graphene Quantum Dots
- Excitonic absorption in gate controlled graphene quantum dots
- Excitonic Fano Resonance in Freestanding Graphene
- Edge-dependent selection rules in magic triangular graphene flakes
- Electronic structure of triangular, hexagonal and round graphene flakes near the Fermi level
- High-energy excitonic effects in graphite and graphene
- Magnetic field dependence of the exciton energy in a quantum disk
- Excitonic effects in the optical conductivity of gated graphene
- Alternative Fourier Expansions for Inverse Square Law Forces
- Formation and control of electron molecules in artificial atoms: Impurity and magnetic-field effects
- Transition to Landau Levels in Graphene Quantum Dots
- Dirac electrons in graphene-based quantum wires and quantum dots
- Zero-energy states of graphene triangular quantum dots in a magnetic field
- Electron-electron interactions in bilayer graphene quantum dots
- Dirac equation description on the electronic states and magnetic properties of a square graphene quantum dot
Cited by in corpus (5)
- The role of impurities on the optical properties of rectangular graphene flakes
- The optical selection rules of a graphene quantum dot in external electric fields
- Anomalous energy shift of laterally confined two-dimensional excitons
- Electrically-induced polarization selection rules of a graphene quantum dot
- Wannier Excitons Confined in Hexagonal Boron Nitride Triangular Quantum Dots