AlbaNova Colloquium

Visualizing Many Body Quantum States in Magical Flat Bands

by Ali Yazdani (Princeton)

When electrons live in electronic bands without any momentum dispersion (flat bands), they are forced to interact strongly with one another. These interactions can give rise to some of the most exotic electronic states known to date, such as the fractional quantum Hall effect, which occur for electrons moving in a plane subjected to strong magnetic fields. Recently, there has been another method to create flat bands, by twisted stacking of two-dimensional crystals and subjecting electrons to move in so-called moiré potentials that forms in such structures. I will show how we use a scanning tunneling microscope (STM) to visualize electronic states in two related instances of electrons moving in the flat bands, when they make correlated insulating phases. The microscopy experiments allow us to tease out what type of correlated electronic states electron are forming and show these state to have remarkable novel quantum texture in their electronic wavefunctions.
Ali Yazdani is  Class of 1909 Professor of Physics at Princeton University and the Director of the Princeton Center for Complex Materials. 
He is a leading expert in the development of quantum microscopy and spectroscopy techniques to study unconventional states of matter.
His awards include Buckley Prize (2023), the most prestigious condensed matter physics prize of the Americal Physical Society.  He is a member of the US National Academy of Sciences, Fellow of the American Academy of Arts and Sciences,  American Association for the Advancement of Science and of the American Physical Society