TY - JOUR
T1 - Effect of Charge Order on the Plasmon Dispersion in Transition-Metal Dichalcogenides
AU - van Wezel, Jasper
AU - Schuster, Roman
AU - König, Andreas
AU - Knupfer, Martin
AU - van den Brink, Jeroen
AU - Berger, Helmuth
AU - Büchner, Bernd
PY - 2011/10/18
Y1 - 2011/10/18
N2 - We investigate the dispersion of the charge carrier plasmon in the three prototypical charge-density wave bearing transition-metal dichalcogenides 2H-TaSe2, 2H-TaS2 and 2H-NbSe2 employing electron energy-loss spectroscopy. For all three compounds the plasmon dispersion is found to be negative for small momentum transfers. This is in contrast to the generic behavior observed in simple metals as well as the related system 2H-NbS2, which does not exhibit charge order. We present a semiclassical Ginzburg-Landau model which accounts for these observations, and argue that the vicinity to a charge ordered state is thus reflected in the properties of the collective excitations.
AB - We investigate the dispersion of the charge carrier plasmon in the three prototypical charge-density wave bearing transition-metal dichalcogenides 2H-TaSe2, 2H-TaS2 and 2H-NbSe2 employing electron energy-loss spectroscopy. For all three compounds the plasmon dispersion is found to be negative for small momentum transfers. This is in contrast to the generic behavior observed in simple metals as well as the related system 2H-NbS2, which does not exhibit charge order. We present a semiclassical Ginzburg-Landau model which accounts for these observations, and argue that the vicinity to a charge ordered state is thus reflected in the properties of the collective excitations.
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80054745368&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.107.176404
DO - 10.1103/PhysRevLett.107.176404
M3 - Article (Academic Journal)
C2 - 22107547
SN - 0031-9007
VL - 107
SP - 1
EP - 5
JO - Physical Review Letters
JF - Physical Review Letters
IS - 17
M1 - 176404
ER -