BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//talks.cam.ac.uk//v3//EN
BEGIN:VTIMEZONE
TZID:Europe/London
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:BST
DTSTART:19700329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19701025T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
CATEGORIES:Theory of Condensed Matter
SUMMARY:Topological electronic properties of silicon - Pro
 f. Claudio Chamon\, Boston University
DTSTART;TZID=Europe/London:20171005T141500
DTEND;TZID=Europe/London:20171005T151500
UID:TALK83581AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/83581
DESCRIPTION:The central role that materials play in human hist
 ory is exemplified by the three-age division of pr
 ehistory into the stone\, bronze\, and iron ages. 
 References to our present time as the information 
 age or silicon age epitomizes the important role t
 hat this semiconducting material came to play in t
 he development of computers and devices that perme
 ate our daily lives. Remarkably\, silicon has been
  left out of the explosion of research activity on
  topological materials. On the surface\, this omis
 sion is the result of a boundary-centric classific
 ation of undoped\nsilicon as a “trivial insulator”
 . Here we show that the electronic states in silic
 on have nontrivial topological structures that are
  captured by a network of Berry flux lines that li
 nk at points of high symmetry in the Brillouin zon
 e. This complex network has ice-nodal points where
  fluxes satisfy ice rules. Fixing the longitudinal
  momentum parallel to such flux lines yields a two
 -dimensional Dirac Hamiltonian for the transverse 
 degrees of freedom. This complex Berry-flux networ
 k implies a topologically stable two-fold degenera
 cy along the X-W\ndirection in all of silicon band
 s\, a fact that is supported by crystal symmetry a
 rguments as well as direct inspection of the vast 
 literature on silicon band structures.
LOCATION:TCM Seminar Room\, Cavendish Laboratory
CONTACT:Bartomeu Monserrat
END:VEVENT
END:VCALENDAR