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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-8382
DTSTART:20230831T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260414T033343Z
LAST-MODIFIED:20230814T151434Z
LOCATION:5310 Chamberlin Hall
SUMMARY:Integer and fractional Chern insulators in twisted bilayer MoT
 e2  \, R. G. Herb Condensed Matter Seminar\, Yihang Zeng\, Cornell
DESCRIPTION:Chern insulators\, which are the lattice analogs of the qu
 antum Hall states\, can potentially manifest high-temperature topologi
 cal orders at zero magnetic field to enable next-generation topologica
 l quantum devices. To date\, integer Chern insulators have been experi
 mentally demonstrated in several systems at zero magnetic field\, but 
 fractional Chern insulators have been reported only in graphene-based 
 systems under a finite magnetic field. The emergence of semiconductor 
 moiré materials\, which support tunable topological flat bands\, open
 s a new opportunity to realize fractional Chern insulators. In this ta
 lk\, I will present evidence for both integer and fractional Chern ins
 ulators at zero magnetic field in small-angle twisted bilayer MoTe2. C
 ombining our newly developed local electronic compressibility measurem
 ent and magneto-optical measurement\, we find the system is incompress
 ible and spontaneously breaks time reversal symmetry at hole filling f
 actor 1 and 2/3. We show that they are integer and fractional Chern in
 sulators\, respectively\, from their dispersion in filling factor with
  applied magnetic field. I will further demonstrate electric-field-tun
 ed topological phase transitions involving the Chern insulators. Our f
 indings pave the way for demonstration of quantized fractional Hall co
 nductance and anyonic excitation and braiding in semiconductor moiré 
 materials.  
URL:https://www.physics.wisc.edu/events/?id=8382
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