Ballistic quantum transport at high energies and high magnetic fields

TL;DR

This paper extends the recursive Green's function method to efficiently analyze ballistic quantum transport under high energies and magnetic fields, revealing complex interference effects and wavefunction localization.

Contribution

The authors develop a new extension of the modular recursive Green's function method to include magnetic fields, enabling high-accuracy analysis of quantum transport in previously inaccessible regimes.

Findings

Observation of multi-frequency Aharonov-Bohm oscillations

Classification of fluctuations as Fano resonances

Localization of wavefunctions near classical trajectories

Abstract

We present an extension of the modular recursive Green's function method (MRGM) for ballistic quantum transport to include magnetic fields. Dividing the non-separable two-dimensional scattering problem into separable substructures allows us to calculate transport coefficients and scattering wavefunctions very efficiently. Previously unattainable energy and magnetic field regions can thereby be covered with high accuracy. The method is applied to magnetotransport through a circle and a stadium shaped quantum dot at strong magnetic fields and high energies. In the edge state regime we observe strong multi-frequency Aharonov-Bohm oscillations. By analyzing them in terms of a multi-channel interference model, we classify these fluctuations within the framework of Fano resonances and discuss their geometry independence. For high energies (mode numbers) we observe localization of the scattering wavefunction near classical trajectories.