Landau levels, edge states and magneto-conductance in GaAs/AlGaAs core-shell nanowires

TL;DR

This paper models the magnetic states and magneto-conductance in GaAs/AlGaAs core-shell nanowires, revealing how electron interactions and prismatic geometry influence electronic properties and anisotropic conductance.

Contribution

It provides a comprehensive, self-consistent model incorporating realistic device features and electron interactions, advancing understanding of magnetic and transport phenomena in nanowires.

Findings

Landau levels and edge states dominate at low carrier densities.

Electron-electron interactions cause inhomogeneous localization at higher densities.

Magneto-conductance shows strong anisotropy linked to prismatic geometry.

Abstract

Magnetic states of the electron gas confined in modulation-doped core-shell nanowires are calculated for a transverse field of arbitrary strength and orientation. Magneto-conductance is predicted within the Landauer approach. The modeling takes fully into account the radial material modulation, the prismatic symmetry and the doping profile of realistic GaAs/AlGaAs devices within an envelope-function approach, and electron-electron interaction is included in a mean-field self-consistent approach. Calculations show that in the low free-carrier density regime, magnetic states can be described in terms of Landau levels and edge states, similar to planar two-dimensional electron gases in a Hall bar. However, at higher carrier density the dominating electron-electron interaction leads to a strongly inhomogeneous localization at the prismatic heterointerface. This gives rise to a complex band dispersion, with local minima at finite values of the longitudinal wave vector, and a region of negative magneto-resistance. The predicted marked anisotropy of the magneto-conductance with field direction is a direct probe of the inhomogeneous electron gas localization of the conductive channel induced by the prismatic geometry.