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The Anthony J Leggett Institute for Condensed Matter Theory Seminar - "Non-Abelian Fractionalizations and Anyon Superconductivity in Small-Angle Twisted Bilayer MoTe2" (Gil Young Cho, POSTECH University of Science and Technology (Pohang, Korea))

Event Type
Seminar/Symposium
Sponsor
Physics - The Anthony J Leggett Institute for Condensed Matter Theory
Location
ESB Lab 3110
Date
Aug 1, 2025   11:00 am - 12:00 pm  
Speaker
Gil Young Cho
Contact
Thierry Ramais
E-Mail
ramais@illinois.edu
Phone
217-300-2044
Originating Calendar
Physics - The Anthony J Leggett Institute for Condensed Matter Theory Seminar

AbstractTwisted bilayer MoTe₂ has recently attracted significant attention due to the experimental realization of long-sought fractional Chern insulators. In this talk, we present a theoretical study of twisted bilayer MoTe₂ near a 2-degree twist angle, motivated by recent experiments reporting non-Abelian fractional quantum spin Hall insulators in its second moiré band. We show that this small-angle twisted bilayer MoTe₂ hosts a sequence of topological Chern bands that closely mimic the structure of Landau levels. In particular, the first and second moiré bands exhibit striking similarities to the lowest and first Landau levels, respectively, as evidenced by their quantum geometric properties and the correspondence of band-projected interactions to Haldane pseudopotentials. These results establish twisted bilayer MoTe₂ as a promising platform for realizing non-Abelian fractional Chern insulators and fractional quantum spin Hall states. In the second part of the talk, we demonstrate the emergence of a time-reversal symmetric superconducting phase proximate to the fractional spin Hall insulator. This superconductivity arises from purely repulsive interactions much larger than the bandwidth and features a mixed pairing state that combines conventional s-wave and unconventional i-wave components with angular momentum Lz=6. These features point to a nontrivial, potentially exotic origin of superconductivity that we identify as anyon superconductivity. 

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