Landauer-B\"uttiker approach for hyperfine mediated electronic transport in the integer quantum Hall regime

TL;DR

This paper develops a Landauer-B"uttiker framework to analyze hyperfine interaction effects on electronic transport in the integer quantum Hall regime, revealing hysteresis and nuclear polarization phenomena.

Contribution

It introduces a self-consistent simulation of nuclear and electronic dynamics and extends circuit models to include quadrupolar splitting effects.

Findings

Hysteresis in conductance-voltage traces explained by nuclear-electronic non-equilibrium.

Circuit models successfully emulate hyperfine mediated transport effects.

Signatures of multi-photon processes identified in transport measurements.

Abstract

The interplay of spin-polarized electronic edge states with the dynamics of the host nuclei in quantum Hall systems presents rich and non-trivial transport physics. Here, we develop a Landauer-B\"uttiker approach to understand various experimental features observed in the integer quantum Hall set ups featuring quantum point contacts. The approach developed here entails a phenomenological description of spin resolved inter-edge scattering induced via hyperfine assisted electron-nuclear spin flip-flop processes. A self-consistent simulation framework between the nuclear spin dynamics and edge state electronic transport is presented in order to gain crucial insights into the dynamic nuclear polarization effects on electronic transport and in turn the electron-spin polarization effects on the nuclear spin dynamics. In particular, we show that the hysteresis noted experimentally in the conductance-voltage trace as well as in the resistively detected NMR lineshape results from a lack of quasi-equilibrium between electronic transport and nuclear polarization evolution. In addition, we present circuit models to emulate such hyperfine mediated transport effects to further facilitate a clear understanding of the electronic transport processes occurring around the quantum point contact. Finally, we extend our model to account for the effects of quadrupolar splitting of nuclear levels and also depict the electronic transport signatures that arise from single and multi-photon processes.