Coexistence of electron whispering-gallery modes and atomic collapse states in graphene WSe2 heterostructure quantum dots

Abstract

The relativistic massless charge carriers with a Fermi velocity of about c300 in graphene enable us to realize two distinct types of resonances (c, the speed of light in vacuum). One is electron whispering-gallery mode in graphene quantum dots arising from the Klein tunneling of the massless Dirac fermions. The other is atomic collapse state, which has never been observed in experiment with real atoms due to the difficulty of producing heavy nuclei with charge Z 170, however, can be realized near a Coulomb impurity in graphene with a charge Z 1 because of the small velocity of the Dirac excitations. Here, unexpectedly, we demonstrate that both the electron whispering-gallery modes and atomic collapse states coexist in grapheneWSe2 heterostructure quantum dots due to the Coulomb-like potential near their edges. By applying a perpendicular magnetic field, evolution from the atomic collapse states to unusual Landau levels in the collapse regime are explored for the first time.

References in corpus (12)

• The electronic properties of graphene
• Chiral tunneling and the Klein paradox in graphene
• The Coulomb impurity problem in graphene
• Vacuum Polarization and Screening of Supercritical Impurities in Graphene
• Atomic Collapse and Quasi-Rydberg States in Graphene
• Creating and Probing Electron Whispering Gallery Modes in Graphene
• An On/Off Berry Phase Switch in Circular Graphene Resonators
• Tuning a Circular p-n Junction in Graphene from Quantum Confinement to Optical Guiding
• Generating nanoscale and atomically-sharp p-n junctions in graphene via monolayer-vacancy-island engineering of Cu surface
• Magnetic field driven instability of charged center in graphene
• Magnetic field dependence of the atomic collapse state in graphene
• Coulomb impurity problem of graphene in magnetic fields

Cited by in corpus (8)

• Direct Visualization of Relativistic Quantum Scars
• Tunable Sample-wide Electronic Kagome Lattice in Low-angle Twisted Bilayer Graphene
• Orbital hybridization in graphene-based artificial atoms
• Magnetic field-tunable valley-contrasting pseudomagnetic confinement in graphene
• Molecular Collapse States in Elliptical Graphene/WSe2 Heterostructure Quantum Dots
• Absence of edge states at armchair edges in inhomogeneously strained graphene under a pseudomagnetic field
• Atomic collapse of high-order singular potentials in graphene
• Current-induced re-entrant superconductivity and extreme nonreciprocal superconducting diode effect in valley-polarized systems