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

Abstract
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, T_P, 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 T_P 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 T_P.