Valley isospin of interface states in a graphene $pn$ junction in the quantum Hall regime

Abstract

In the presence of crossed electric and magnetic fields, a graphene ribbon has chiral states running along sample edges and along boundaries between $p$-doped and $n$-doped regions. We here consider the scattering of edge states into interface states, which takes place whereever the $pn$ interface crosses the sample boundary, as well as the reverse process. For a graphene ribbon with armchair boundaries, the evolution of edge states into interface states and {\em vice versa} is governed by the conservation of valley isospin. Although valley isospin is not conserved in simplified models of a ribbon with zigzag boundaries, we find that arguments based on isospin conservation can be applied to a more realistic modeling of the graphene ribbon, which takes account of the lifting of electron-hole degeneracy. The valley isospin of interface states is an important factor determining the conductance of a graphene $pn$ junction in a quantizing magnetic field.

13 pages, 13 figures

References in corpus (19)

• Electric Field Effect in Atomically Thin Carbon Films
• The electronic properties of graphene
• Valley filter and valley valve in graphene
• Andreev reflection and Klein tunneling in graphene
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Edge States and the Quantized Hall Effect in Graphene
• Quantized Transport in Graphene p-n Junctions in Magnetic Field
• Disorder-induced enhancement of transport through graphene p-n junctions
• Stabilization mechanism of edge states in graphene
• Conductance quantization and snake states in graphene magnetic waveguides
• Snake States in Graphene p-n Junctions
• Graphene p-n junction Arrays as Quantum-Hall Resistance Standards
• Quantum limit of the triplet proximity effect in half-metal - superconductor junctions
• Disorder Effects in the Quantum Hall Effect of Graphene p-n Junctions
• All-strain based valley filter in graphene nanoribbons using snake states
• Graphene n-p junction in a strong magnetic field: a semiclassical study
• Giant valley-isospin conductance oscillations in ballistic graphene
• Chiral interface states in graphene $p$-$n$ junctions
• Graphene pn-junction in a quantizing magnetic field: Conductance at intermediate disorder strength

Cited by in corpus (8)

• Quantum Hall valley splitters and tunable Mach-Zehnder interferometer in graphene
• Emission and Coherent Control of Levitons in Graphene
• Phase diagrams and edge-state transitions in graphene with spin-orbit coupling and magnetic and pseudomagnetic fields
• Fragility of surface states in non-Wigner Dyson topological insulators
• Optical valley separation in two-dimensional semimetals with tilted Dirac cones
• How do edge states position themselves in a quantum Hall graphene pn junction?
• Time-dependent transport in Graphene Mach-Zender Interferometers
• Asymmetric-gate Mach--Zehnder interferometry in graphene: Multi-path conductance oscillations and visibility characteristics