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SUMMARY:Interaction of phonons and Dirac fermions on the surface of Bi2Se3
 : A strong Kohn anomaly - Michael El-Batanouny\, Department of Physics\, B
 oston University\, USA
DTSTART:20111027T150000Z
DTEND:20111027T160000Z
UID:TALK31625@talks.cam.ac.uk
CONTACT:Stephen Walley
DESCRIPTION:Strong TIs have exotic metallic surface states protected by ti
 me-reversal invariance (TRI). The linear dispersion of these surface state
 s\, Dirac cones\, depicts massless Dirac fermion quasi-particles with defi
 nite helicity\, whereby the spin is locked normal to the wavevector of the
  electronic state. Helium atom/surface scattering measurements of phonon d
 ispersion curves on the (001) surface of the strong three-dimensional topo
 logical insulator Bi2Se3 reveal a prominent signature of the exotic metall
 ic Dirac fermion quasi-particles\, including a strong Kohn anomaly. The si
 gnature is manifest in a low energy isotropic convex dispersive surface ph
 onon branch with a frequency maximum of 1.8 THz\, and having a V-shaped mi
 nimum at approximately 2kF that defines the Kohn anomaly.
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
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