论文标题
通过电子辅助的两级系统的纳米力学阻尼
Nanomechanical damping via electron-assisted relaxation of two-level systems
论文作者
论文摘要
我们报告了覆盖有铝制的纳米力学设备的Millikelvin温度下的耗散和频率噪声的测量。将金属层从超导下切换到具有磁场的正常状态后，会观察到明显的过量阻尼。除了连接到声子浴的内部隧道系统的标准模型之外，我们在这里考虑了传导电子的松弛以及压力/未压力设备的机械分散法的性质。借助这些关键成分，由于与电子和声子与良好分开的时间表的相互作用，描述了结构内两级系统的松弛模型，可捕获数据。此外，我们在正常状态下测量过量的1/f型频率噪声，这进一步强调了传导电子的影响。
We report on measurements of dissipation and frequency noise at millikelvin temperatures of nanomechanical devices covered with aluminum. A clear excess damping is observed after switching the metallic layer from superconducting to the normal state with a magnetic field. Beyond the standard model of internal tunneling systems coupled to the phonon bath, here we consider the relaxation to the conduction electrons together with the nature of the mechanical dispersion laws for stressed/unstressed devices. With these key ingredients, a model describing the relaxation of two-level systems inside the structure due to interactions with electrons and phonons with well separated timescales captures the data. In addition, we measure an excess 1/f-type frequency noise in the normal state, which further emphasizes the impact of conduction electrons.
