Valley-kink in Bilayer Graphene at $\nu =0$: A Charge Density Signature for Quantum Hall Ferromagnetism

Abstract

We investigate interaction-induced valley domain walls in bilayer graphene in the $\nu =0$ quantum Hall state, subject to a perpendicular electric field that is antisymmetric across a line in the sample. Such a state can be realized in a double-gated suspended sample, where the electric field changes sign across a line in the middle. The non-interacting energy spectrum of the ground state is characterized by a sharp domain wall between two valley-polarized regions. Using the Hartree-Fock approximation, we find that the Coulomb interaction opens a gap between the two lowest-lying states near the Fermi level, yielding a smooth domain wall with a kink configuration in the valley index. Our results suggest the possibility to visualize the domain wall via measuring the charge density difference between the two graphene layers, which we find exhibits a characteristic pattern. The width of the kink and the resulting pattern can be tuned by the interplay between the magnetic field and gate electric fields.

References in corpus (10)

• The electronic properties of graphene
• Unconventional quantum Hall effect and Berry's phase of 2pi in bilayer graphene
• Asymmetry gap in the electronic band structure of bilayer graphene
• Quantum Hall Ferromagnetism in Graphene
• Landau Level Splitting in Graphene in High Magnetic Fields
• Topological confinement in bilayer graphene
• Edge States and the Quantized Hall Effect in Graphene
• Dissipative Quantum Hall Effect in Graphene near the Dirac Point
• Intra-Landau level Cyclotron Resonance in Bilayer Graphene
• Skyrme and Wigner crystals in graphene

Cited by in corpus (3)

• Helical Edge States and Quantum Phase Transitions in Tetralayer Graphene
• Transport gap and hysteretic behavior of the Ising quantum Hall ferromagnets in Landau levels $\left|N\right|>0$ of bilayer graphene
• Probing Layer Localization in Twisted Graphene Bilayers via Cyclotron Resonance