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SUMMARY:Splitting in the Fermi surface of ZrTe3: A surface charge density 
 wave system - Moritz Hoesch\, Diamond Light Source\, Harwell\, Oxon
DTSTART:20090521T150000Z
DTEND:20090521T160000Z
UID:TALK17106@talks.cam.ac.uk
CONTACT:Stephen Walley
DESCRIPTION:The Charge Density Wave (CDW) in ZrTe_3 is driven by a Fermi-s
 urface nesting of the quasi 1-dimensional Fermi surface sheet of the Te p_
 x orbitals. The layered material is made of prismatic ZrTe_3 chains that a
 re laterally linked through Te p-bonding. The CDW develops below T_CDW = 6
 3 K with a modulation vector q_CDW in the a*-c*-plane perpendicular to the
  prismatic chains.\n\nIn this seminar I will present lattice dynamics data
  from inelastic x-ray scattering (IXS) that show the soft mode mechanism o
 f the charge density wave and reveal the thermodynamics of the phase trans
 ition far from mean field behaviour. A set of high resolution angle resolv
 ed photoemission (ARPES) data shows the opening of a gap in the Fermi surf
 ace and allows the determination of its magnitude.\n\nA comparison of the 
 observed electron dispersions with a first principles calculation shows th
 at the surface sensitive ARPES is not compatible with the expected bulk el
 ectronic structure. Rather\, the surface relaxation gives rise to a subtly
  modified behaviour in the top layer. This leads to the interesting\nconcl
 usion that controlled modifications of the CDW system are possible at the 
 surface and their properties can be studied by surface sensitive technique
 s.\n
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
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