# Théorie et simulation du transport quantique dans les nanostructures

Abstract : This theoretical work focuses on the electronic quantum transport in nanostructures. We used the theoretical framework of the Landauer and post-Landauer approaches. The critical point within these approaches in order to correctly describe the transport problem is the approximation on the self-energies, which are supposed to represent simultaneously contact resistance effects as well as interactions in the device. In this work, we adressed both these issues. In order to describe the contact resistance mechanisms, we developped a method based on the effective conductance channels concept. The recursive calculation of these channels, together with the derivation of a new formula of the conductance, provide us with an exact description of the contact effects. Moreover, we built a new \textit{ab initio} methodology, which allows us to introduce the electron-electron interactions in the quantum transport through the Hedin's $GW$ approximation of the self-energy. The second part of this work deals with the analysis of the transport properties of graphene. We firstly analysed the experimental magneto-resistance characteristics of epitaxial graphene, and explained them by a mechanism consecutive to the planes stacking. Eventually, we calculated the conductance characteristics of devices compound by graphene nanostructures. We shown that such devices exhibit very high contact resistance effects, which can be explained by means of electron diffraction. We introduced the electronic diffraction barrier concept, which allows us to extract conductance characteristics, without determining the electronic structure.
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https://tel.archives-ouvertes.fr/tel-00363630
Contributor : Pierre Darancet <>
Submitted on : Tuesday, February 24, 2009 - 7:17:18 PM
Last modification on : Friday, December 18, 2020 - 1:12:04 PM
Long-term archiving on: : Saturday, November 26, 2016 - 6:08:27 AM

### Identifiers

• HAL Id : tel-00363630, version 2

### Citation

Pierre Darancet. Théorie et simulation du transport quantique dans les nanostructures. Physique [physics]. Université Joseph-Fourier - Grenoble I, 2008. Français. ⟨tel-00363630v2⟩

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