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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-4567
DTSTART:20171214T160000Z
DURATION:PT1H0M0S
DTSTAMP:20260313T151108Z
LAST-MODIFIED:20171211T122214Z
LOCATION:5310 Chamberlin Hall
SUMMARY:Graphene in the extreme quantum limit\, R. G. Herb Condensed M
 atter Seminar\, Cory Dean\, Columbia University
DESCRIPTION:Soon after the discovery of monolayer graphene\, it was sh
 own that bilayer graphene (BLG)\, consisting of two bernal stacked mon
 olayers\,  could theoretically support an even-denominator fractional 
 quantum Hall state equivalent to the 5/2 Moore-Read Pfaffian first ide
 ntified in GaAs . Owing to the unique landau level spectrum in BLG\, t
 he Pfaffian in this system is expected to be tunable by electric and m
 agnetic fields\, with the potential to be stronger than in GaAs for ac
 cessible field parameters. In my talk I will discuss recent magnetotra
 nsport studies of high mobility\, BLG. Utilizing a dual gate geometry 
 to tune through different orbital and layer polarizations\, we find fo
 ur even denominator states appearing within the N = 1 orbital branches
  of the lowest LL. We investigate how these states evolve with varying
  parameters and provide the first mapping of the B – D phase diagram
 . Our results confirm the unique tunability of the even denominator st
 ate in BLG\, and we reach a regime where the energy gap is found to ex
 ceed several kelvin.  I will also present recent measurements of bilay
 er systems in which we separate the two layers by a thin BN spacer.  H
 ere\, by tuning the interlayer interaction strength via the layer sepa
 ration\, we are able to stabilize new correlated states in the double 
 layer systems formed from interlayer excitons.
URL:https://www.physics.wisc.edu/events/?id=4567
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