2Dseminars@Grenoble : Measuring graphene’s Berry phase from wavefront dislocations in Friedel oscillations
Jeudi 26 septembre 2019 11:00
- Duree : 1 heure
Lieu : Salle du bâtiment accueil, CEA - 17 rue des Martyrs - Grenoble
Orateur : Clément DUTREIX
Abstract :
The knowledge of electronic band structures is central to understand the electrical and optical features of solids. If the band-structure spectrum is routinely measured through various techniques, it is more challenging to access the topological properties of the wave functions, such as quantized Berry phases. In graphene, the ultra-relativistic behavior of the electrons is associated with a phase singularity of the wave functions in momentum space. This behavior is traditionally evidenced by measuring a topological Berry phase picked up by the wave functions orbiting around the phase singularity, when applying a perpendicular magnetic field [1]. During this seminar, we will introduce a new approach to probe the phase singularity in the absence of magnetic field, with a scanning tunneling microscope. We will show that the phase singularity manifests itself in real space, in the way the charge density rearranges around an impurity, through a phenomenon commonly believed unobservable in quantum mechanics so far [2].
[1] K. S. Novoselov et al., Nature 438, 197 (2005) ; Y. Zhang et al., Nature 438, 201 (2005) ; D. Xiao et al., RMP 82, 1959 (2010)
[2] C. Dutreix, H. Gonzalez-Herrero, I. Brihuega, M. I. Katsnelson, C. Chapelier, and V. T. Renard, Nature, in press
Contact : claude.chapelier@cea.fr
Discipline évènement : (Physique)
Entité organisatrice : (INAC/SPSMS)
Nature évènement : (Séminaire)
Site de l'évènement : Site CEA sans badge requis
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