Transport properties of TaS3 and NbSe3 crystals of nanometer-scale transverse dimensions

The finite-size effect in transport properties of quasi-one-dimensional conductors TaS3 and NbSe3 with the charge-density wave (CDW) has been studied in crystals having the room-temperature unit length resistance R(300 K)/L up to 10(5) Omega/mum, which corresponds to the transverse sizes of the crystals around 10 nm. The transition from room-temperature metallic behavior (dR/dT>0) to nonmetallic one (dR/dT<0) accompanied by disappearance of the Peierls transition is observed in crystals having R/Lsimilar to10 kOmega/mum, in agreement with the earlier observations. Further, sample size reduction leads to substantial modification of the shape of R(T) curves. Possible physical mechanisms of the phenomena, including growth of CDW fluctuations, transition to the commensurable CDW, development of the Luttinger-liquid-like behavior, surface effects, impurity effects, 1D Friedel oscillations, etc. are analyzed. (C) 2003 Elsevier B.V. All rights reserved.