Transport properties of TaS3 crystals of nanometer-scale transverse dimensions
Serguei.V. Zaitsev-Zotov ( serzz-AT-cplire-DOT-ru.gif )
Institute of Radioengineering and Electronics of Russian Academy of Sciences, 101999 Moscow, Mokhovaya 11, Russia.
Systematic study of the finite-size effect in transport properties of quasi-one-dimensional conductor TaS$_3$ with the charge-density wave has been undertaken in crystals having unit length resistance $R/L$ up to $10^5$ Ohm/$\mu$m, which corresponds to the transverse sizes of the crystals around 1 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 $R/L~10$ kOhm/$\mu$m, in agreement with the earlier observation [1]. Further sample size reduction leads to substantial modification of the shape of $R(T)$ curves, especially at temperatures above the Peierls transition temperature of bulk crystals. Highly nonlinear I-V curves are observed in a wide temperature region. Possible physical mechanisms of the phenomena, including growth of charge-density wave fluctuations, development of the Luttinger-liquid-like behavior, surface effects, impurity effects (1D Friedel oscillations) etc, are analyzed.

[1] S.V. Zaitsev-Zotov, V.Ya. Pokrovskii, and P. Monceau, Pis'ma v ZhETP, 73, 29 (2001) [JETP Letters, 73, 25 (2001)].