BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//RLASKEY//CALENDEROUS//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260813T004550Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20110422T160000Z
DTEND:20110422T170000Z
UID:event807@bu.edu
URL:http://physics.bu.edu/internal/events/show/807
SUMMARY:Visualizing Surface States of Topological Insulators with Scanning 
	Tunneling Microscopy 
DESCRIPTION:Featuring Pedram Roushan\, Princeton University\nHosted by: Arm
	in Rahmanisisian\n\nPart of the Biophysics/Condensed Matter Seminar Series.
	\n\nAbstract:\n\n In topological insulators\, the spin texture of the surfa
	ce states makes them distinct from conventional two-dimensional electron st
	ates\, and leads to novel properties for these states. These surface states
	 are expected to be immune to localization and to overcome barriers caused 
	by material imperfections. We have used scanning tunneling microscopy and s
	pectroscopy to study the topological surface states in BiSb\, Sb\, Bi2Te3 a
	nd Bi2Se3. By mapping the interference of the surface states scattering off
	 random alloying disorder in BiSb\, we have demonstrated that despite stron
	g atomic scale disorder\, backscattering between states of opposite momentu
	m and opposite spin is absent\, resulting from the spin texture. Furthermor
	e\, we have measured the transmission and reflection of topological surface
	 states of Sb through atomic terraces. In contrast to Schottky surface stat
	es of noble metals\, these surface states penetrate such barriers with high
	 probability. To examine the possibility of disorder induced localization\,
	 we investigated the surface states of Bi2Te3 and Bi2Se3 in the presence of
	 local defects. We have observed an interference pattern throughout a broad
	 range of energies\, even in the region of linear dispersion near the Dirac
	 point.  We discuss the results of a statistical analysis of these pat
	terns which can help to learn about the tendency toward localization for th
	ese surface states and how this trend is affected as the energy is tuned to
	 the Dirac point.\n\n  
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
END:VCALENDAR