Magnetic superlattice and finite-energy Dirac points in graphene

TL;DR

This paper investigates how a one-dimensional magnetic superlattice in graphene creates new finite-energy Dirac points with anisotropic dispersion, enabling potential control of Dirac quasiparticle trajectories through doping.

Contribution

It reveals the emergence of finite-energy Dirac points with anisotropic dispersion in graphene's band structure due to a magnetic superlattice, a novel finding.

Findings

Discovery of new finite-energy Dirac points at the superlattice Brillouin zone center.

Anisotropic dispersion near these finite-energy Dirac points.

Potential for collimating Dirac quasiparticles by tuning doping levels.

Abstract

We study the band structure of graphene's Dirac-Weyl quasi-particles in a one-dimensional magnetic superlattice formed by a periodic sequence of alternating magnetic barriers. The spectrum and the nature of the states strongly depend on the conserved longitudinal momentum and on the barrier width. At the center of the superlattice Brillouin zone we find new Dirac points at finite energies where the dispersion is highly anisotropic, in contrast to the dispersion close to the neutrality point which remains isotropic. This finding suggests the possibility of collimating Dirac-Weyl quasi-particles by tuning the doping.