Plasmon evolution and charge-density wave suppression in potassium intercalated 2H-TaSe2
1 IFW Dresden, Institute for Solid State Research - P. O. Box 270116, D-01171 Dresden, Germany
2 Institut de Physique de la Matière Condensée, EPFL - CH-1015 Lausanne, Switzerland
Received: 25 June 2012
Accepted: 20 September 2012
We have investigated the influence of potassium intercalation on the formation of the charge-density wave (CDW) instability in 2H-TaSe2 by means of electron energy-loss spectroscopy and density functional theory. Our observations are consistent with a filling of the conduction band as indicated by a substantial decrease of the plasma frequency in experiment and theory. In addition, elastic scattering clearly points to a destruction of the CDW upon intercalation as can be seen by a vanishing of the corresponding superstructures. This is accompanied by a new superstructure, which can be attributed to the intercalated potassium. Based on the behavior of the c-axis upon intercalation we argue in favor of interlayer sites for the alkali metal and that the lattice remains in the 2H modification.
PACS: 71.45.Lr – Charge-density-wave systems / 71.20.Tx – Fullerenes and related materials; intercalation compounds / 71.15.Mb – Density functional theory, local density approximation, gradient and other corrections
© EPLA, 2012