The sliding of the room-temperature charge density wave (CDW) in the monoclinic phase of $\mathrm{Nb}{\mathrm{S}}_3$ under rf power is studied. The threshold field, $E_{\mathrm{t}}$, and Shapiro steps’ width, δE, show aperiodic Bessel-type oscillations as a function of rf voltage. Here we demonstrate experimentally that, if presented as a function of CDW path length in each half period of the rf voltage, $E_{\mathrm{t}}$ and δE show periodic oscillations, the period being equal to the CDW wavelength. The result is found to be universal for different compounds and gives clear understanding of the synchronization effects in terms of forced oscillations of a particle in a periodic potential.

中文翻译：

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射频同步模式下电荷密度波的逐步推进以及夏皮罗阶梯宽度的振动相对于所施加的射频功率的变化

室温单斜相中室温电荷密度波（CDW）的滑动 $铌{\mathrm{小号}}_3$在射频功率下进行了研究。阈值字段，${Ë}_{\mathrm{Ť}}$，以及Shapiro台阶的宽度δE，显示出非周期Bessel型振荡与rf电压的关系。在这里，我们通过实验证明，如果将其表示为rf电压每个半周期中CDW路径长度的函数，${Ë}_{\mathrm{Ť}}$和δE显示周期振荡，所述周期等于所述CDW波长。发现该结果对于不同的化合物是通用的，并且根据粒子在周期性电势中的强迫振荡给出了对同步效应的清晰理解。