Collective Dynamics of One-Dimensional Charge Density Waves

The effect of disorder on the static and dynamic behaviour of one-dimensional charge density waves at low temperatures is studied by analytical and numerical approaches. In the low temperature region the spatial behaviour of the phase-phase correlation function is dominated by disorder but the roughness exponent remains the same as in the pure case. Contrary to high dimensional systems the dependence of the creep velocity on the electric field is described by an analytic function.Comment: 4 pages, 4 figure

Impurity effect on low-temperature polarisation of the charge-density-waves in o-TaS3_3

The temperature dependence of the low-temperature dielectric response is studied in o-TaS$_3$ samples doped by Nb, Se, and Ni and for nominally pure ones. It is found, that the low-temperature dielectric constant depends anomalously on doping and is higher for doped crystals, whereas the temperature dependence of the characteristic time of all samples follows the activation law with nearly the same activation energy $\sim 400$ K (T>20 K). The observed behaviour is inconsistent with all available explanations of the low-temperature dielectric anomaly.Comment: RevTex, 12 pages, epsf, 2 postscript Figures. Accepted for publication in Physics Letters

Contributions of high-energy excitations to the linear and non-linear conduction near the Peierls transition

Very thin samples of TaS3 (cross-section area ∼ 10-3 µm2) are found to demonstrate smearing of the I-V curves near the threshold field in the Peierls state. With approaching the Peierls transition temperature, TP, the smearing evolves into smooth growth of conductance from zero voltage, interpreted by us as the contribution of fluctuations to the non-linear conductance. The fluctuation contribution to the linear conductance near TP is identified independently. Both linear and non-linear contributions depend on temperature with close activation energies ∼ (2 - 4) x 103 K and apparently reveal the same process. We reject creep of the continuous charge-density waves (CDW) as an origin of the effect and show that it is spontaneous phase slippage that results to creep of the CDW. A model is proposed accounting for both the linear and non-linear parts of the fluctuation conduction up to TP

Impurity-induced metal-insulator transition in quasi-one-dimensional metals TaSe3_{3} and NbSe3_{3}

A metal-insulator transition induced by impurity incorporation was observed in TaSe$_3$ and NbSe$_3$ samples. It was found out that the conduction of nanometer-scale thickness TaSe$_3$ samples exhibits behavior expected for one-dimensional electron systems. Thick micrometer-scale NbSe$_3$ samples with impurities introduced by thermal diffusion show a behavior similar to the one observed earlier in nanoscale sample

Variable-range-hopping-like transverse conductivity of the quasi one-dimensional conductor TaS3_{3}

We report temperature dependence of transverse conductivity and its hysteresis in TaS$_3$. The results argue that the conductivity mechanism is variable-range hopping (VRH)

Transport properties of N bSe3 crystals with nanometer-scale transverse dimensions

A systematic study of the finite-size effects in transport properties of NbSe$_3$ crystals has been undertaken in crystals having room-temperature unit length resistance up to 10$^5~\Omega \mu$m. A substantial modification of the shape of the resistance vs. temperature curves, $R(T)$, is observed for the thinnest crystals. The measurements of the resistance and the Shapiro steps show that the effective cross-section area responsible for single-electron and CDW transport is substantially below a sample cross-section area defined by atomic force and scanning electron microscopy. A time evolution of the $R(T)$ is found. It is shown that the observed time evolution is similar to one resulted from breaking of the chains. Thus for thinnest samples, the contribution from a$^*$ and c-axis transport should be taken into account

Spatially-resolved studies of charge-density-wave phase slip and dynamics in NbSe3

We review our spatially and temporally resolved studies of charge-density-wave (CDW) phase slip and dynamics in NbSe3. Measurements of the steady-state CDW current, phase slip and strain profiles and their transient evolutions in response to a change in current direction provide a detailed picture of the interplay between elastic deformations and plasticity in this material