From Local to Non-Local Transport : Percolation in Quantum Hall Systems, Cross-Correlations in Superconducting Hybrid Structures
type: Dataset
description: This thesis consists of two independent parts. The first one deals with transport in two dimensional electron gases in the regime of the quantum Hall effect. In the second part, current and current cross-correlations are studied in normal conductor-superconductor-normal conductor (NSN) hybrid structures. In the high temperature regime of the quantum Hall effect, the longitudinal conductance is calculated in a diagrammatic formalism based on a local conductivity approach. It takes the interplay between electron-phonon scattering and the drift motion along equipotential lines of the disorder potential into account and provides a microscopic derivation of the universal transport critical exponent that was up to now only conjectured from qualitative geometrical arguments. Microscopic expressions for the dependence in temperature and magnetic field of the longitudinal conductance are derived and compared to recent experiments. In the low temperature regime of the quantum Hall effect, tunneling over saddle points is studied from the scattering of semi-coherent state wave packets. We derive analytically the transmission coefficient of saddle-points in the scalar potential in graphene and find that asymmetric saddle-points break particle-hole symmetry in the conductance. In three-terminal NSN hybrid structures the influence of additional barriers on the (non-local) conductance and on current cross-correlations is studied with scattering theory. In metallic, phase averaged systems additional barriers lead to an enhancement of local processes by reflectionless tunneling but have little influence on non-local processes and on current cross-correlations. In ballistic systems, additional barriers lead to Fabry-Perot oscillations and allow to distinguish the different contributions to the conductance and to the current cross-correlations.
landing page: https://theses.hal.science/tel-00866133
identifier: NNT: 2012GRENY049
keyword: effet-hall-quantique
keyword: effet-tunnel
keyword: infoeu-reposemanticsdoctoralthesis
keyword: percolation
keyword: physcondcm-genphysics-physicscondensed-matter-cond-matother-cond-matother
keyword: quantum-hall-effect
keyword: quantum-transport
keyword: scattering-theory
keyword: structures-hybrides-supraconductrices
keyword: superconducting-hybrid-structures
keyword: theorie-de-diffusion
keyword: theses
keyword: transport-quantique
keyword: tunneling
issued: 2026-05-09T14:42:11.314174
modified: 2026-05-09T14:42:11.314178
language: fr
contact point: Organization
  fn: CCSD

test_moissonnage_selune
type: Agent

From Local to Non-Local Transport : Percolation in Quantum Hall Systems, Cross-Correlations in Superconducting Hybrid Structures
type: Distribution
format: HTML
access URL: https://theses.hal.science/tel-00866133
issued: 2026-05-09T14:42:11.316663
modified: 2026-05-09T14:42:11.300654