Abstract
At T ≈ 100 K, the magnitude of the shear compliance of TaS3 increases by 25% with charge-density-wave (CDW) depinning by a dc voltage. We have measured the strain frequency dependence of the complex compliance (j) at different voltages, and fit it to distributions of Debye relaxation modes. The sensitivity of the compliance to the structure of the CDW suggests that it would also be sensitive to a glass transition. However, we find that both the real and imaginary parts of j are independent of frequency (within 1%) when the CDW remains pinned for 8 K < T < 70 K. j is also independent (0.1%) of the frequency of small applied voltages, for which the dielectric constant varies greatly. Therefore, if there is a glass transition at these temperatures, these results imply that either it does not involve rearrangement of the CDW domain structure or that the elastic response time remains > 1 s for the pinned CDW.
| Original language | English |
|---|---|
| Pages (from-to) | 2671-2674 |
| Number of pages | 4 |
| Journal | Synthetic Metals |
| Volume | 103 |
| Issue number | 1-3 |
| DOIs | |
| State | Published - Jun 24 1999 |
| Event | Proceedings of the 1998 International Conference on Science and Technology of Synthetic Metals (ICSM-98) - Montpellier Duration: Jul 12 1998 → Jul 18 1998 |
Bibliographical note
Funding Information:currents affect the elastic properties, we have measured J and 9 (at fixed fs) as a function of the frequency (fv) of a small, constant (v < VT/lo) ac san@e voltage sptig the frequency range where dielectric anomalies are observed [2,3]. Results at several temperatures, for fa = 23 Hz, are shown in Figures 6 and 7. Since these data do not have to be normalized to NbSes results, the errors are smaller than for fB measurements. No dependence of J (+ 0.1%) or Q (?~0.02’) on fv was observed. Thus we observe no dependence of the complex i on either the strain or voltage frequency at any temperature below 70 K. This suggests that if there is a glass transition at these temperatures, then it does not involve bulk changes in the CDW structure. For example, it has been suggested that the glass transition involves freeze-in of localized (soliton-like) CDW distortions 133,w hich might have negligible effect on the elastic properties. (However, we note that it has been argued that solitons would aiso have negligible effects on the transport properties of a CDW material [17].) Alternatively, if there are bulk CDW structural changes, then their average time constant is greater than l/~(minimum) = 1.6 s at all temperatures, even above the transitions, and hence are not directly responsible for the faster dielectric behavior. (Similarly, the elastic depinning spectra shown in Figure 2 involve much longer time constants than those observed in the dielectric response [18].) We thank R.E. Thome for providing crystals and D.K. Powell for technical assistance. This research was supported by the U.S. National ScienceF oundation, grant DMR-9300507.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry