Graphene: Kinks, Superlattices, Landau levels, and Magnetotransport

TL;DR

This review explores the electronic properties of superlattices in graphene, focusing on quasiparticle behavior, Landau levels, topological modes, and potential device applications, highlighting recent experimental and theoretical advances.

Contribution

It provides a comprehensive overview of how superlattice potentials influence graphene's electronic structure, including new Dirac modes, topological states, and magnetotransport phenomena.

Findings

Quasiparticle chirality induces tunable Dirac modes in superlattices.

Magnetic fields can reverse transport anisotropy in monolayer graphene.

Topological kink modes in bilayer graphene can form tunable Luttinger liquids.

Abstract

We review recent work on superlattices in monolayer and bilayer graphene. We highlight the role of the quasiparticle chirality in generating new Dirac fermion modes with tunable anisotropic velocities in one dimensional (1D) superlattices in both monolayer and bilayer graphene. We discuss the structure of the Landau levels and magnetotransport in such superlattices over a wide range of perpendicular (orbital) magnetic fields. In monolayer graphene, we show that an orbital magnetic field can reverse the anisotropy of the transport imposed by the superlattice potential, suggesting possible switching-type device applications. We also consider topological modes localized at a kink in an electric field applied perpendicular to bilayer graphene, and show how interactions convert these modes into a two-band Luttinger liquid with tunable Luttinger parameters. The band structures of electric field superlattices in bilayer graphene (with or without a magnetic field) are shown to arise naturally from a coupled array of such topological modes. We briefly review some bandstructure results for 2D superlattices. We conclude with a discussion of recent tunneling and transport experiments and point out open issues.