NORMAL-STATE ELECTRODYNAMIC PROPERTIES OF CHARGE-DENSITY-WAVE AND SPIN-DENSITY-WAVE COMPOUNDS

We have examined the normal state (T > T-c) optical properties (1-10(5 ) cm(-1)) of low dimensional conductors which exhibit both charge- and spin-density-wave ground states and have found important deviations f rom simple metallic behavior, especially at low frequencies. In additi on to a pseudogap, the optical response parallel to the conducting cha ins of the charge-density-wave (CDW) compound (TaSe4)(2)I (T-c = 263 K ) shows an enhanced low frequency conductivity which can be described quantitatively as the contribution from fluctuating CDW segments. Simi larly, we will present optical measurements performed on the model spi n-density-wave (SDW) compound (TMTSF)(2)PF6 (T-c = 12.1 K). In the met allic state just above T-c, the optical conductivity parallel to the c onducting chains has two distinct temperature dependent features: a ze ro frequency response and a finite energy absorption.