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BEGIN:VEVENT
DTSTAMP:20260912T132351Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20110325T193000Z
DTEND:20110325T203000Z
UID:event742@bu.edu
URL:http://physics.bu.edu/internal/events/show/742
SUMMARY:Spontaneous Nanoscale Pattern Formation Induced by Ion Bombardment 
	of Solid Surfaces 
DESCRIPTION:Featuring Mark Bradley\, Colorado State University\nHosted by: 
	Karl Ludwig\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\nA
	bstract:\nBombarding a solid surface with a broad ion beam can produce a re
	markable variety of self-assembled nanoscale patterns.  The spontaneous eme
	rgence of these patterns is not just fascinating in its own right\, since i
	n the future ion bombardment may prove to be an important tool in the fabri
	cation of nanostructures.  \n\nAs an introduction to the field\, the questi
	on of why oblique-incidence ion bombardment often produces periodic height 
	modulations or "ripples" on a solid surface will be addressed.  I will then
	 move on to discuss a theory we have developed that explains the genesis of
	 the strikingly regular hexagonal arrays of nanodots that can form when a f
	lat surface of a binary compound is subjected to normal-incidence ion bomba
	rdment. As we have demonstrated analytically\, nanodot arrays with short-ra
	nge hexagonal order emerge spontaneously for a certain range of the paramet
	ers.  In our theory\, the coupling between the topography and a thin surfac
	e layer of altered stoichiometry is the key to the pattern formation.
LOCATION: \, \, 
STATUS:CONFIRMED
CLASS:PUBLIC
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