Hu Xiaoli, Egberts Philip, Dong Yalin, Martini Ashlie
School of Engineering, University of California Merced, 5200 N. Lake Road, Merced, CA 95343, USA.
Nanotechnology. 2015 Jun 12;26(23):235705. doi: 10.1088/0957-4484/26/23/235705. Epub 2015 May 20.
Molecular dynamics (MD) simulations were used to model amplitude modulation atomic force microscopy (AM-AFM). In this novel simulation, the model AFM tip responds to both tip-substrate interactions and to a sinusoidal excitation signal. The amplitude and phase shift of the tip oscillation observed in the simulation and their variation with tip-sample distance were found to be consistent with previously reported trends from experiments and theory. These simulation results were also fit to an expression enabling estimation of the energy dissipation, which was found to be smaller than that in a corresponding experiment. The difference was analyzed in terms of the effects of tip size and substrate thickness. Development of this model is the first step toward using MD to gain insight into the atomic-scale phenomena that occur during an AM-AFM measurement.
分子动力学（MD）模拟被用于对幅度调制原子力显微镜（AM-AFM）进行建模。在这个新颖的模拟中，模型原子力显微镜探针既对探针与基底的相互作用做出响应，也对正弦激励信号做出响应。在模拟中观察到的探针振荡的幅度和相移及其随探针 - 样品距离的变化，被发现与先前报道的实验和理论趋势一致。这些模拟结果还拟合了一个能够估计能量耗散的表达式，结果发现该能量耗散比相应实验中的要小。从探针尺寸和基底厚度的影响方面对这种差异进行了分析。该模型的开发是朝着利用分子动力学深入了解AM-AFM测量过程中发生的原子尺度现象迈出的第一步。
