Spatial horizons in amplitude and frequency modulation atomic force microscopy
Spatial horizons in amplitude and frequency modulation atomic force microscopy
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DOI：
10.1039/c2nr12012g
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发表时间：
2012-01-01
期刊：
影响因子：
6.7
通讯作者：
Chiesa, Matteo
中科院分区：
文献类型：
--
作者：
Font, Josep;Santos, Sergio;Chiesa, Matteo
在动态原子力显微镜（AFM）中，悬臂梁振动并监测其动力学以探测具有纳米级和原子分辨率的样品。振幅和频率调制原子力显微镜（AM-AFM和FM-AFM）已成为该领域最强大的方法。尽管如此，在特定的培养基或实验中，究竟哪一种技术更好，仍然是有争议的。在这里，我们定量地建立和比较这两种技术的分辨率的限制，通过引入空间视界（SH）的概念，并量化它。SH是限制空间边界超过集体原子相互作用不影响一个给定的反馈系统的检测参数。我们表明，虽然FM-AFM反馈可以解决一个单一的原子或原子缺陷的AM反馈可能会失败，相对对比度实际上是等效的两个反馈系统。也就是说，如果AM反馈可以检测到足够小的振幅偏移并且没有噪声，则AM-AFM和FM-AFM中对单个原子或原子缺陷的检测将是等效的。
In dynamic atomic force microscopy (AFM) the cantilever is vibrated and its dynamics are monitored to probe the sample with nanoscale and atomic resolution. Amplitude and frequency modulation atomic force microscopy (AM-AFM and FM-AFM) have established themselves as the most powerful methods in the field. Nevertheless, it is still debatable whether one or the other technique is preferred in a given medium or experiment. Here, we quantitatively establish and compare the limitations in resolution of both techniques by introducing the concept of spatial horizon (SH) and quantifying it. The SH is the limiting spatial boundary beyond which collective atomic interactions do not affect the detection parameters of a given feedback system. We show that while an FM-AFM feedback can resolve a single atom or atomic defect where an AM feedback might fail, relative contrast is in fact equivalent for both feedback systems. That is, if the AM feedback could detect sufficiently small amplitude shifts and there was no noise, the detection of single atoms or atomic defects would be equivalent in AM-AFM and FM-AFM.