Engineering quantum coherence in the integer quantum Hall effect regime
type: Dataset
description: This PhD thesis is devoted to the engineering of quantum coherence in the integer quantum Hall effect regime (IQHE) at filling factor ν=2, obtained by applying a strong perpendicular magnetic field to a bidimensional electron gas formed at the interface of a GaAlAs/GaAs semiconducting heterostructure. Then unidimensional chiral conductors called edge states appear which can be used as electron beams to build the equivalent in condensed matter of a Mach-Zehnder interferometer (MZI) so as to study coherence in this regime. The unexpected periodic lobe structure of the visibility as function of the bias voltage suggests that interactions play an important role.In the first part, we explain how edge states emerge in the IQHE regime. We picture the state of the art on the edge states coherence. Then we present the MZI from the experimental point of view.Next we show our results, first concerning the visibility at finite bias: our measurements confirm a prediction about a quantum phase transition as function of the interfering edge state dilution. We don't see any significant manifestation of energy relaxation in the visibility. Finally, having identified the adjacent edge state as the noisy environment limitating coherence thanks to previous works, we have designed a new kind of sample to decrease the coupling of the system to this environment in a controlled manner. We thus decreased dephasing by half, in quantitative agreement with the theory developped previously in our group.
identifier: NNT: 2012PA112021
issued: 2026-05-23T05:33:52.217845
language: en
modified: 2026-05-23T05:33:52.217850
contact point: Organization
  fn: CCSD
keyword: coherence-quantique
keyword: edge-states
keyword: effet-hall-quantique-entier
keyword: etats-de-bord
keyword: infoeu-reposemanticsdoctoralthesis
keyword: integer-quantum-hall-effect
keyword: interactions
keyword: physcondcm-genphysics-physicscondensed-matter-cond-matother-cond-matother
keyword: quantum-coherence
keyword: theses
landing page: https://theses.hal.science/tel-00683582

Engineering quantum coherence in the integer quantum Hall effect regime
type: Distribution
format: HTML
issued: 2026-05-23T05:33:52.253796
modified: 2026-05-23T05:33:52.192987
access URL: https://theses.hal.science/tel-00683582

test_moissonnage_selune
type: Agent