Research Seminars @ Illinois

View Full Calendar

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

Anthony J Leggett Institute for Condensed Matter Theory Special Seminar - "Doping a fractional quantum anomalous Hall insulator"

Event Type: Seminar/Symposium
Sponsor: Physics - The Anthony J Leggett Institute for Condensed Matter Theory
Location: MRL 280
Date: Dec 4, 2024 12:00 pm
Speaker: Zhengyan (Darius) Shi, Massachusetts Institute of Technology
Contact: Stephen Bullwinkel
E-Mail: bullwink@illinois.edu
Phone: 217-333-1652
Views: 47
Originating Calendar: Physics - The Anthony J Leggett Institute for Condensed Matter Theory Seminar; The recent discovery of fractional quantum anomalous Hall (FQAH) insulators in two-dimensional van der Waals materials opens the door to an amazing variety of strongly correlated electronic phases and phase transitions beyond the conventional quantum Hall setting at large magnetic fields. In this talk, I describe several novel compressible phases that can be accessed by doping incompressible FQAH states realized in a fractionally filled Chern band. Unlike in the lowest Landau level, where single-electron motion is confined into cyclotron orbits, electrons in a Chern band occupy Bloch states with well-defined crystal momenta. At a non-zero doping density, this enables the formation of itinerant states of the doped anyons just beyond the FQAH plateau region. Near the Jain state at 2/3 filling, we find three types of compressible phases, depending on which anyon has the lowest excitation gap. These include a topological superconductor with chiral neutral fermion edge modes as well as a more exotic Pair Density Wave (PDW) superconductor with coexisting non-Abelian topological order. In addition to superconductors, we also find a CDW metal that arises from pairing instabilities of a non-Fermi liquid that can emerge near filling 2/3 at intermediate temperatures. Though inspired by the theory of anyon superconductivity, our construction is qualitatively different, primarily due to filling constraints associated with the lattice translation symmetry. If time permits, I will also discuss the unusual transport signatures associated with each phase and analyze the crossover between different finite-temperature regimes.

link for robots only