Noise and ac-dc interference phenomena in the charge-density-wave conductor K0.3MoO
Noise and ac-dc interference phenomena in the charge-density-wave conductor K0.3MoO
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电荷密度波导体 K0.3MoO 中的噪声和交直流干扰现象
DOI：
10.1103/physrevb.39.3026
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Zettl
中科院分区：
文献类型：
--
作者：
Hundley;Zettl
我们证明了在直流电场驱动下，电荷密度波(CDW)导体的超薄(L1m厚)样品显示出高质量的窄带噪声谱。在组合直流和大幅值交流场的存在下，CDW变为与外部信号锁定的模式，从而导致DC I-V特性中的Shapiro阶跃。在交流场和小幅值交流场联合作用下，当内、外频率重合时，复数交流电导率中的共振特征明显。对Shapiro阶跃干扰的分析表明，交直流干扰是驱动电场与低频介电弛豫模之间的直接耦合。交流电导率中的共振被证明类似于移相谐振子中存在的那些。噪声和干扰实验都给出了窄带噪声频率与${f}_{\mathrm{NBN}/{J}_{\mathrm{CDW}}}$=12\ifmmode\pm\else\textpm\fi{}3 kHz值之间的比值，表明本征钉扎势的周期等于连续波波长。
We demonstrate that extremely thin (l1 \ensuremath{\mu}m thick) samples of the charge-density-wave (CDW) conductor ${\mathrm{K}}_{0.3}$${\mathrm{MoO}}_{3}$ display high-quality narrow-band noise spectra when driven by a dc electric field. In the presence of combined dc and large-amplitude ac fields, the CDW becomes mode locked to the external signal, giving rise to Shapiro steps in the dc I-V characteristics. In the presence of combined dc and small-amplitude ac fields, distinct resonance features in the complex ac conductivity \ensuremath{\sigma}(\ensuremath{\omega}) are observed whenever the internal and external frequencies coincide. Analysis of the Shapiro-step interference suggests that the ac-dc interference arises from a direct coupling between the driving fields and the low-frequency dielectric relaxation mode in ${\mathrm{K}}_{0.3}$${\mathrm{MoO}}_{3}$. Resonances in the ac conductivity are shown to be analogous to those present in a phase-shifted resonant harmonic oscillator. Both noise and interference experiments yield a ratio between the narrow-band noise frequency and the CDW current-density of ${f}_{\mathrm{NBN}/{J}_{\mathrm{CDW}}}$=12\ifmmode\pm\else\textpm\fi{}3 kHz ${\mathrm{cm}}^{2}$/A, suggesting that the intrinsic pinning potential in ${\mathrm{K}}_{0.3}$${\mathrm{MoO}}_{3}$ has a periodicity equal to the CDW wavelength.