Phase coherence in the current-carrying charge-density-wave state: ac-dc coupling experiments in NbSe 3
Phase coherence in the current-carrying charge-density-wave state: ac-dc coupling experiments in NbSe 3
复制标题
载流电荷密度波状态下的相位相干性：NbSe 3 中的交流-直流耦合实验
DOI：
10.1103/physrevb.29.755
复制
发表时间：
1984
影响因子：
3.7
通讯作者：
G. Grüner
中科院分区：
文献类型：
--
作者：
A. Zettl;G. Grüner
报道了线性链状化合物NbSe 3的电荷密度波（CDW）态的各种实验，包括直流和交流驱动场的联合应用，V= Vdc + Vaccos（ω t）.当施加交流驱动场时，在直流I− V特性中观察到阶跃。复交流响应σ ac（ω）也受到直流场的强烈影响，对于明确定义的驱动频率和偏置场，σ ac（ω）会发生急剧变化。这些现象是施加的交流信号和固有电流振荡之间的干扰效应的结果。在这两种情况下，交流“干扰”频率与电荷密度波携带的过量电流I CDW成比例。我们分析了我们的实验中提出的一个简单的非线性方程的字段和频率相关的响应和电流振荡现象。该方程在形式上与描述反向分流约瑟夫森结（Stewart-McCumber模型）的方程相同。在这个方程的分析导致一个高度一致的样品响应，其中的标本可以描述由一个单一的自由度。我们的观察结果也讨论了最近的理论CDW钉扎和动力学。
Various experiments which involve the joint application of dc and ac driving fields, V= V dc+ V ac cos (ω t), are reported for the charge-density-wave (CDW) state of the linear-chain compound Nb Se 3. Steps are observed in the dc I− V characteristics when ac driving fields are applied. The complex ac response σ ac (ω) is also strongly influenced by the application of dc fields, with sharp changes occurring in σ ac (ω) for well-defined driving frequencies and bias fields. These phenomena are the consequence of interference effects between the applied ac signal and the intrinsic current oscillations. In both cases, the ac" interference" frequency is proportional to the excess current I CDW carried by the charge-density wave. We analyze our experiments in terms of a simple nonlinear equation proposed previously to account for the field-and frequency-dependent response and current oscillation phenomena. The equation is formally identical to the equation describing a resistively shunted Josephson junction (Stewart-McCumber model). Analysis in terms of this equation leads to a highly coherent sample response where the specimen can be described by a single degree of freedom. Our observations are also discussed in light of recent theories of CDW pinning and dynamics.