From laterally modulated two-dimensional electron gas towards artificial graphene

TL;DR

This study investigates how lateral patterning in GaAs/AlGaAs heterostructures influences the electronic miniband structure, revealing conditions to emulate graphene physics through cyclotron resonance measurements and theoretical modeling.

Contribution

It introduces a perturbative approach to describe the effects of lateral potentials on 2D electron gases and establishes criteria for achieving graphene-like electronic properties.

Findings

Observed non-linear cyclotron resonance behavior and mode splitting.

Linked patterning parameters to effective potential and miniband tuning.

Formulated criteria for realizing graphene-like physics in patterned heterostructures.

Abstract

Cyclotron resonance has been measured in far-infrared transmission of GaAs/Al$_x$Ga$_{1-x}$As heterostructures with an etched hexagonal lateral superlattice. Non-linear dependence of the resonance position on magnetic field was observed as well as its splitting into several modes. Our explanation, based on a perturbative calculation, describes the observed phenomena as a weak effect of the lateral potential on the two-dimensional electron gas. Using this approach, we found a correlation between parameters of the lateral patterning and the created effective potential and obtain thus insights on how the electronic miniband structure has been tuned. The miniband dispersion was calculated using a simplified model and allowed us to formulate four basic criteria that have to be satisfied to reach graphene-like physics in such systems.