论文标题
纳米膜中弯曲热运动的弹道动力学以亚原子分辨率揭示
Ballistic Dynamics of Flexural Thermal Movements in a Nano-membrane Revealed with Subatomic Resolution
论文作者
论文摘要
独立式膜，纳米膜和纳米线的弯曲振荡正在引起人们对2D材料的热，电气和机械性能的重要性的越来越多的关注。在这里，我们报告了在弯曲声子的热波动驱动的纳米膜悬臂弯曲模式下的短时弹道运动的观察，包括使用新的自由电子距离划分的弹性速度测量弹道速度和以亚原子分辨率进行的位移。在<10μs的间隔内，膜以恒定速度（通常约为300μm/s）进行弹道移动，而布朗（Brownian）类似动力学则在更长的观察周期内出现。访问弹道制度提供了对弯曲模式的均衡定理和麦克斯韦 - 波尔兹曼统计的验证，并且可以在膜上原子吸收/解吸过程中的快速温度和质量传感中使用。我们认为，应在理解2D材料的电气，光学，热和机械性能时考虑弹道制度。
Flexural oscillations of free-standing films, nano-membranes and nano-wires are attracting growing attention for their importance to the thermal, electrical and mechanical properties of 2D materials. Here we report on the observation of short-timescale ballistic motion in the flexural mode of a nano-membrane cantilever, driven by thermal fluctuation of flexural phonons, including measurements of ballistic velocities and displacements performed with sub-atomic resolution, using a new free electron edge-scattering technique. Within intervals <10 μs, the membrane moves ballistically at a constant velocity, typically ~300 μm/s, while Brownian-like dynamics emerge for longer observation periods. Access to the ballistic regime provides verification of the equipartition theorem and Maxwell-Boltzmann statistics for flexural modes, and can be used in fast thermometry and mass sensing during atomic absorption/desorption processes on the membrane. We argue that the ballistic regime should be accounted for in understanding the electrical, optical, thermal and mechanical properties of 2D materials.
