On Monday, July 3, 2023, at 12:00 p.m. c.t., the next meeting of our Physics Colloquium will take place.
The speaker is Prof. Dr. Thomas Weitz (Georg-August University of Göttingen) on the topic "Complex quantum phases in flat-band van-der-Waals systems: making, controlling and measuring by quantum transport"..
The exchange interaction can lead to correlated states in low dimensional systems such as the graphene family. Regions of large density of states are especially prone to correlation effects. In this talk I will give an introduction into the making of flat-band systems by Morié or electrostatic engineering. I will also discuss how to probe such states by low temperature charge transport. Finally I will discuss two of our recent experiments. First, the recently identified exchange driven quantum anomalous Hall (QAH) nu=2 state that exhibits quantized charge Hall conductance close to zero magnetic field as well as spin, valley and spin-valley anomalous quantum Hall effects and out-of-plane ferroelectricity in suspended bilayer graphene. And second our recent measurements in h-BN encapsulated Bernal bilayer graphene where we realized flat electronic bands at an electric-field tunable van-Hove-singularity and placed the Fermi level in them via electrostatic gating. In such device structures we have found indications of exotic states consistent with for example a Chern insulator finite density in the valence band.
Abstract of the presentation by Prof. Weitz.
The introduction will be given by Prof. Dr. Michael Scherer.
The faculty cordially invites all interested parties. The event will take place in lecture hall HNB and hybrid via Zoom. Before the colloquium we offer coffee and cookies. This link will take you to the Zoom event (meetingID: 632 5520 9938, password: 526977). All dates of the Physics Colloquium can be found here.