Pantheon SEMPARIS Le serveur des séminaires parisiens Paris

Statut Confirmé
Domaines cond-mat
Date Lundi 14 Fevrier 2022
Heure 13:30
Institut LPENS
Salle L361
Nom de l'orateur Pillet
Prenom de l'orateur Jean-Damien
Addresse email de l'orateur
Institution de l'orateur Ecole Polytechnique
Titre Guiding Dirac Fermions in Graphene with a Carbon Nanotube
Résumé Relativistic massless charged particles in a two-dimensional conductor can be guided by a one-dimensional electrostatic potential, in an analogous manner to light guided by an optical fiber. In this seminar, I will present how we use a carbon nanotube to generate such a guiding potential in graphene and create a single mode electronic waveguide. In our architecture, the nanotube and graphene are separated by a few nanometers and can be controlled and measured independently. As we charge the nanotube close to the surface of graphene, we observe in the latter the formation of a single guided mode that we detect using the same nanotube as a probe. I will discuss why the small dimensions of the nanotube and the linear dispersion relation of Dirac fermions gives these electronic waveguides promising characteristics for potential applications. I will also show that, in presence of magnetic field, our electronic waveguides host discrete electronic levels resembling Landau levels of 2D Dirac particles but with no C-symmetric counterpart, i.e. they exist only for one sign of energy, positive or negative, depending on the voltage applied on the nanotube. This unusual behavior is a generic signature of Dirac surface states, which are predicted to be protected to a great extent to surface disorder.
Numéro de preprint arXiv
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