S. Brazovskii, P. Monceau and N. Kirova
J. Phys. IV France 131 (2005) 305-305
Charge density wave gap in ZrTe3A. Perucchi1, L. Degiorgi1 and H. Berger2
1 Laboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich, Switzerland
2 Department of Physics, EPF Lausanne, 1015 Lausanne, Switzerland
The transition metal trichalcogenides ( MX3, M= Ta, Ti, Nb and X= Se, S, Te) have been widely studied as prototype examples of linear chain conductors exhibiting novel charge density wave (CDW) phenomena. The title compound is semimetallic with linear chain structure but quasi-two-dimensional conductivity. At TCDW=63 K it undergoes a phase transition, which most strongly affects its conductivity components perpendicular to the conducting chains, and it becomes superconducting at 2 K. We have measured the optical reflectivity from the far-infrared up to the ultraviolet spectral range as a function of temperature and with light polarized both along and perpendicular to the chains. Through Kramers-Kronig transformation we have extracted the optical conductivity. We found optical evidence for the CDW gap, which opens over a tiny amount of the Fermi surface. The temperature dependence of the gap follows the BCS behaviour for an order parameter. The role played by fluctuation effects will be also discussed.
© EDP Sciences 2005