Valley properties of doped graphene in a magnetic field

TL;DR

This paper investigates the electronic properties of doped graphene in a magnetic field, revealing valley-specific behaviors, impurity effects, and potential for polarized valley current manipulation through magnetic tuning.

Contribution

It provides a detailed theoretical analysis of valley-dependent electronic and magnetic properties of doped graphene under magnetic fields, including impurity effects and scattering contributions.

Findings

Valley-specific density of states differences observed.

Band gap induced by asymmetric impurity concentration.

Magnetization shifts with impurity energy, enabling valley current control.

Abstract

The aim of this work is to describe the electronic properties of graphene in a constant magnetic field in the long wavelength approximation with random binary disorder, by solving the Soven equation self-consistently. Density of state contributions for different valleys in each sublattice sites are obtained for different values of magnetic field strength showing remarkable differences between K and K' valleys. A band gap is obtained by an asymmetric on-site impurity concentration and the graphene electrons acquire an anomalous magnetic moment, which is opposite in different valleys, which depend highly in the interplay between the impurity band, the band edges and the broadening of the Landau levels. In turn, magnetization as a function of B for different on-site random impurities is computed showing that by decreasing the on-site impurity energy values, maximum magnetization is shifted towards higher values of B which can be used to create and manipulate polarized valley currents. Finally, conductivity and local vertex function are obtained as a function of energy showing that scattering contributions from A and B sublattices differ significantly. Effective medium local two-irreducible vertex is computed showing that scattering from sublattices A and B do not contribute equally, which can be related to weak anti-localization. From these results, it could be possible to explore how the valley pseudospin can be used to create polarized currents by populating asymmetrically the sublattice sites, where the population can be tuned with the applied magnetic field strength.