Amplitude dependence of image quality in atomically-resolved bimodal atomic microscopy
Abstract
In bimodal FM-AFM, two flexural modes are excited simultaneously. The total vertical oscillation deflection range of the tip is the sum of the peak-to-peak amplitudes of both flexural modes (sum amplitude). We show atomically resolved images of KBr(100) in ambient conditions in bimodal AFM that display a strong correlation between image quality and sum amplitude. When the sum amplitude becomes larger than about 200 pm, the signal-to-noise ratio (SNR) is drastically decreased. We propose this is caused by the temporary presence of one or more water layers in the tip-sample gap. These water layers screen the short range interaction and must be displaced with each oscillation cycle. Further decreasing the sum amplitude, however, causes a decrease in SNR. Therefore, the highest SNR in ambient conditions is achieved when the sum amplitude is slightly less than the thickness of the primary hydration layer.
Keywords
Cite
@article{arxiv.1605.06584,
title = {Amplitude dependence of image quality in atomically-resolved bimodal atomic microscopy},
author = {Hiroaki Ooe and Dominik Kirpal and Daniel S. Wastl and Alfred J. Weymouth and Toyoko Arai and Franz J. Giessibl},
journal= {arXiv preprint arXiv:1605.06584},
year = {2016}
}
Comments
3000 words, 3 Figures, 3 supplimentary figures