Imaging nematic quantum Hall states and their interacting boundary modes
Mallika Randeria
Pappalardo Fellow in Physics: 2019-2022
Department of Physics
Massachusetts Institute of Technology (MIT)
Présentation en anglais
Vidéoconférence, Zomm #: 892019835 (Zoom link)
Lorsque demandé, indiquer 'zéro zéro deux quatre sept deux' en chiffre.
Abstract: Two-dimensional quantum Hall systems offer a versatile platform to explore the interplay between topology and symmetry breaking facilitated by Coulomb interactions. In this talk, I will discuss novel phenomena that arise from spontaneous valley ordering of bismuth surface states in a large magnetic field. Specifically, we observe the emergence of a nematic phase which breaks the rotational symmetry of the underlying crystal and a ferroelectric phase that carries an in-plane electric dipole moment. We use a scanning tunneling microscope to identify and directly image the wavefunctions of these broken-symmetry quantum Hall phases. Furthermore, we explore the boundary between distinct nematic quantum Hall domains, which host counter-propagating 1D modes. By changing the valley flavor and number of modes, we realize strikingly different regimes where the boundary is either metallic or insulating, constrained by Coulomb interactions between these 1D modes.
For more information about Dr. Randeria, you can consult her research web page.
Cette conférence est présentée par le RQMP.
