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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-7918
DTSTART:20230413T150000Z
DTEND:20230413T160000Z
DTSTAMP:20260414T053002Z
LAST-MODIFIED:20230327T194644Z
LOCATION:5310 Chamberlin
SUMMARY:Valley and Momentum Polarization in Multilayer Graphene\, R. G
 . Herb Condensed Matter Seminar\, Jia Leo Li\, Brown University
DESCRIPTION:Within the flat energy bands of multilayer graphene\, the 
 enhanced influence of Coulomb interaction is reflected by the emergenc
 e of exchange-driven instabilities\, which stabilize isospin-ordered p
 hases by lifting the spin and valley degeneracy. These isospin-ordered
  phases are ubiquitous in the low-temperature phase space of multilaye
 r graphene\, having been observed in Bernal bilayer\, rhombohedral tri
 layer\, and a number of twisted graphene heterostructures near the mag
 ic-angle. Here\, I will discuss a new type of Coulomb-driven instabili
 ty that is driven by the exchange interaction between trigonal-warping
 -induced Fermi pockets. It is recently proposed that such instability 
 could induce a spontaneous condensation of charge carriers into one of
  the Fermi pockets\, giving rise to a net polarization in the momentum
  space. Such exchange-driven instability can be directly probed and ch
 aracterized using angle-resolved nonlinear transport measurement at th
 e second-harmonic frequency. Beyond the experimental identification of
  momentum polarization\, I will discuss its implication on our underst
 anding of electronic orders in the flat energy band of multilayer grap
 hene.
URL:https://www.physics.wisc.edu/events/?id=7918
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