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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-1301
DTSTART:20081023T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260506T190726Z
LAST-MODIFIED:20081015T213204Z
LOCATION:5310 Chamberlin
SUMMARY:Spinons and triplons in a spatially anisotropic triangular lat
 tice antiferromagnet\, R. G. Herb Condensed Matter Seminar\, Oleg Star
 ykh\, University of Utah
DESCRIPTION:Many of the frustrated magnetic materials are characterize
 d by pronounced spatial anisotropy of the exchange interaction between
  spins. I will argue that one can successfully exploit this fact and a
 pproach the problem of frustrated magnetism from a one-dimensional poi
 nt of view\, by treating frustrated inter-chain interactions as a pert
 urbation to a system of decoupled chains.<br>
\n<br>
\nAs a warm-up\, 
 I present a problem of a single Heisenberg chain subject to asymmetric
  Dzyaloshinskii-Moriya interaction and external magnetic field. Rather
  unexpectedly\, the system is found to possess a field-induced long-ra
 nge order of the SDW type.<br>
\n<br>
\nI then proceed with the main f
 ocus of my talk: static and dynamic properties of the spatially anisot
 ropic triangular lattice antiferromagnet\, with inter-chain diagonal e
 xchange J' much weaker than the intrachain exchange J.  Despite retain
 ing magnetic long range order in its ground state\, this spatially ani
 sotropic antiferromagnet exhibits very unusual dynamic response (broad
  continuum) in a wide range of energy and momentum. I will show that t
 he spectrum of excitations from moderate to high energies is composed 
 of incoherent continuum\, arising from the one-dimensional spinons of 
 individual spin chains\, and a sharp dispersing peak\, due to coherent
 ly propagating "triplon" bound states of two spinons. I will present a
  direct and parameter-free comparison of the calculated dynamical spin
  correlations with inelastic neutron measurements on Cs<sub>2</sub>CuC
 l<sub>4</sub>.
URL:https://www.physics.wisc.edu/events/?id=1301
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