Research Seminars @ Illinois

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Tailored for undergraduate researchers, this calendar is a curated list of research seminars at the University of Illinois. Explore the diverse world of research and expand your knowledge through engaging sessions designed to inspire and enlighten.

To have your events added or removed from this calendar, please contact OUR at ugresearch@illinois.edu

MOVED TO 11 AM The Anthony J Leggett Institute for Condensed Matter Physics Seminar: Composite fermions and the fractional quantum anomalous Hall effect

Event Type
Seminar/Symposium
Sponsor
Physics Department
Location
ESB 190
Date
Mar 18, 2024   11:00 am  
Speaker
Hart Goldman, University of Chicago
Contact
Ljubica Milutinovic
E-Mail
ljubicam@illinois.edu
Phone
217-300-6393
Views
73
Originating Calendar
Physics - The Anthony J Leggett Institute for Condensed Matter Theory Seminar

Recent experiments have revealed evidence for fractional quantum anomalous Hall (FQAH) states at zero magnetic field in a growing number of moirĂ© materials. In this talk, I will present a unified theoretical framework for understanding the emergence of FQAH phases in terms of composite fermions, which in the past have played a crucial organizing role in the  phenomenology of 2d electron gases at high magnetic fields. A central prediction of this framework is a non-Fermi liquid metal of composite fermions at even-denominator fillings, which is the parent of the observed FQAH states. To this end, I will present exact diagonalization evidence for such anomalous composite Fermi liquid (ACFL) states at zero magnetic field in twisted MoTe2 bilayers, at fillings n = 1/2 and n = 3/4, and I will argue that these ACFLs play a central role in the FQAH phase diagram. I will also develop a long wavelength theory for ACFL phases, which offers concrete experimental predictions that I will discuss in relation to current measurements. For example, upon doping the composite Fermi sea, one obtains a Jain sequence of FQAH states consistent with those observed experimentally, as well as a new type of commensurability oscillations originating from the superlattice potential intrinsic to the system. Finally, I will discuss how these ideas can launch us into addressing the exciting new questions and research directions in this emerging field. 

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