BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-2537
DTSTART:20120315T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260420T071740Z
LAST-MODIFIED:20120312T124421Z
LOCATION:5310 Chamberlin
SUMMARY:Graphene: it’s all about the surface\, R. G. Herb Condensed 
 Matter Seminar\, Kirill Bolotin\, Vanderbilt University
DESCRIPTION:Every atom of graphene\, a monolayer of graphite\, belongs
  to the surface. Therefore\, the environment of graphene -- the substr
 ate onto which graphene is deposited and the coating on top of graphen
 e -- intimately affects the properties of graphene. In this talk\, we 
 demonstrate that both mechanical and electrical properties of graphene
  can be greatly tuned by varying its environment.  <br>
\n<br>
\nFirst
 \, we discuss ultraclean graphene devices suspended in vacuum. We achi
 eve a carrier mobility in excess of 200\,000 cm2/Vs in these devices a
 nd demonstrate previously inaccessible transport regimes\, including b
 allistic transport and the fractional quantum Hall effect.  <br>
\n<br
 >
\nSecond\, we explore the electrical properties of graphene surround
 ed by liquid dielectrics.  We find that the ions in liquids can cause 
 strong scattering in graphene and demonstrate very large values for ro
 om temperature mobility (>60\,000 cm2/Vs) in ion-free liquids with hig
 h dielectric permittivity.  <br>
\n<br>
\nFinally\, we demonstrate tha
 t the environment of graphene affects its mechanical properties. We de
 velop a novel technique to study the mechanical properties of graphene
  films attached to substrates by measuring the temperature-dependent d
 eflection of a "bimetallic" cantilever composed of graphene and silico
 n nitride or gold layers. We demonstrate that the built-in strain\, th
 e substrate adhesion force and even the thermal expansion coefficient 
 of graphene depend on the substrate under it.  
URL:https://www.physics.wisc.edu/events/?id=2537
END:VEVENT
END:VCALENDAR