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Inertial dynamics of pinned charge-density-wave condensates. I. NbSe 3

1986; American Physical Society; Volume: 34; Issue: 4 Linguagem: Inglês

10.1103/physrevb.34.2212

1095-3795

D. Reagor, S. Sridhar, G. Grüner,

Molecular Junctions and Nanostructures

Conductivity measurements are reported for the linear-chain compound ${\mathrm{NbSe}}_{3}$ in the frequency range 9--100 GHz. In both charge-density-wave (CDW) states, which develop at ${T}_{1}$=144 K and at ${T}_{2}$=59 K, a strongly frequency-dependent response is observed with Re\ensuremath{\sigma}(\ensuremath{\omega}) decreasing with increasing frequency. The behavior is described in terms of a harmonic oscillator response, and in the measured spectral range the expression Re${\ensuremath{\sigma}}_{\mathrm{CDW}}$(\ensuremath{\omega})=(${\mathrm{ne}}^{2}$\ensuremath{\tau}/${m}^{\mathrm{*}}$)[1 /(1+${\ensuremath{\omega}}^{2}$${\ensuremath{\tau}}^{2}$)] provides an excellent account of our findings. We evaluate the effective mass ${m}^{\mathrm{*}}$ and damping constant \ensuremath{\tau} from a fit to the above equation. The measured effective mass is only weakly temperature dependent, and in both CDW states is in good qualitative agreement with those determined using the theory of Lee, Rice, and Anderson. We also discuss the temperature-dependent damping constant, and a comparison with data taken in the radio-frequency range is given.