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DTSTAMP:20260816T114618Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20090213T170000Z
DTEND:20090213T180000Z
UID:event411@bu.edu
URL:http://physics.bu.edu/internal/events/show/411
SUMMARY:Helical Metal Inside a Topological Band Insulator
DESCRIPTION:Featuring Ying Ran\, UC Berkeley\n\nPart of the Biophysics/Cond
	ensed Matter Seminar Series.\n\nAbstract: Topological defects\, such as dom
	ain walls and vortices\, have long fascinated physicists. A novel twist is 
	added in quantum systems like superfluid helium He$_3$\, where vortices are
	 associated with low energy excitations in the cores. Similarly\, cosmic st
	rings which are vortices of the Higgs field\, may be tied to propagating fe
	rmion modes. Can analogous phenomena occur in crystalline solids that host 
	a plethora of topological defects? In this talk I will show that indeed dis
	location lines are associated with one dimensional fermionic excitations in
	 a `topological insulator'\, a novel band insulator believed to be realized
	 in the bulk material Bi$_{0.9}$Sb$_{0.1}$. In contrast to electrons in a r
	egular quantum wire\, these modes are topologically protected\, and not sca
	ttered by disorder. Since dislocations are ubiquitous in real materials\, t
	hese excitations could dominate spin and charge transport in topological in
	sulators. Our results provide a novel route to creating a potentially ideal
	 quantum wire in a bulk solid.
LOCATION: \, \, 
STATUS:CONFIRMED
CLASS:PUBLIC
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