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DTSTAMP:20260917T052515Z
LAST-MODIFIED:20191115T171646Z
DTSTART:20191120T203000Z
DTEND:20191120T220000Z
UID:event2231@bu.edu
URL:http://physics.bu.edu/internal/events/show/2231
SUMMARY:Many-body physics around Van Hove singularities: from twisted bilay
	er graphene to supermetal and non-Fermi liquid
DESCRIPTION:Featuring Hiroki Isobe\, Massachusetts Institute of Technology\
	nHosted by: Claudio Chamon\n\nPart of the Condensed Matter Theory Seminar S
	eries.\n\nSuperconducting and correlated insulating states are observed in 
	graphene multilayers at a magic twist angle.  Tunability of the twist angle
	 and hence the band structure realize nearly flat bands\, where the intrigu
	ing phases appear.  First\, we theoretically study the origin of these corr
	elated states based on a Van Hove singularity (VHS) and Fermi surface nesti
	ng [1].  Then\, we introduce a high-order VHS as a possible explanation for
	 the magic angle\, at which the density of states shows a power-law diverge
	nce [2].  Finally\, we discuss correlation effects at a high-order VHS [3].
	  We perform a renormalization-group analysis to find a nontrivial metallic
	 state\, where various divergent susceptibilities coexist but no long-range
	 order appears.  We term such a metallic state as a supermetal.  Our contro
	lled analysis shows that a supermetal at the interacting fixed point is a n
	on-Fermi liquid.
LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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