Recherche Avancée

Thèse en cours

Epitaxie par jets moléculaires de matértiaux ferromagnétiques à base de GaSb pour les technologies quantiques

FR  |  
EN
Auteur / Autrice : Gallo Sow
Direction : Eric Tournie, Jean-Baptiste Rodriguez
Type : Projet de thèse
Discipline(s) : Électronique
Date : Inscription en doctorat le 30/09/2024
Etablissement(s) : Université de Montpellier (2022-....)
Ecole(s) doctorale(s) : École Doctorale Information, Structures, Systèmes
Partenaire(s) de recherche : Laboratoire : IES - Institut d'Electronique et des Systèmes
Equipe de recherche : Composants à Nanostructures quantiques pour le Moyen InfraRouge (NANOMIR)

Résumé

FR  |  
EN

Since about a decade much fundamental work is devoted to investigate topological and Dirac states in condensed-matter physics. The main interest in these materials is based on their exotic and nontrivial conductive surface or edge properties, which are very attractive for novel electronics and optoelectronics applications. The antimonide semiconductors, i.e. the compound semiconductors based on GaSb, AlSb, InAs, their alloys and heterostructures, have been predicted to exhibit giant topological gaps (>50 meV), and have thus emerged as excellent materials for investigating topological states in condensed matter. 2D topological insulators as well as 2D and 3D Dirac fermions have indeed been experimentally observed, although with narrow topological gaps. In addition, the antimonide technology is the only material platform allowing to create all topological states of the condensed matter (3D topological insulators, Dirac or Weyl semimetals, high order topological states, etc.). The quantum Hall effect (QHE) is used to realize very reproducible resistance values which depend only on fundamental physical constants: the Planck constant h and the electron charge e. Practically, however, the most crucial requirement to realize the QHE is to apply a strong magnetic field, which can be produced in the laboratory only. Ferromagnetism, however, can lead to the so-called anomalous quantum Hall effect (AQHE), a QHE without external magnetic field. In addition, room-temperature ferromagnetism can be achieved with Fe-doped GaSb, with the advantage that Fe3+ being isovalent, it does not introduce free carriers in GaSb. Very few work report on the growth of these materials however. The objective of the PhD research is to develop the MBE growth of ferromagnetic GaSb-based semiconductors and heterostructures for AQHE application. The work will be carried out in close collaboration with Laboratoire Charles Coulomb (L2C), the physics department of U. Montpellier, in the framework of on-going work investigating InAs/GaSb heterostructures for quantum technologies.