Complete information acquisition in dynamic force microscopy.

Alexei Belianinov,Stephen Jesse,Sergei V Kalinin

doi:10.1038/ncomms7550

Alexei Belianinov, Stephen Jesse + Show 1 more

Open Access

https://doi.org/10.1038/ncomms7550

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Journal: Nature Communications	Publication Date: Mar 13, 2015
Citations: 56	License type: cc-by

Affiliation: Oak Ridge National Laboratory

Abstract

Scanning probe microscopy has emerged as a primary tool for exploring and controlling the nanoworld. A critical part of scanning probe measurements is the information transfer from the tip-surface junction to the measurement system. This process reduces responses at multiple degrees of freedom of the probe to relatively few parameters recorded as images. Similarly, details of dynamic cantilever response at sub-microsecond time scales, higher-order eigenmodes and harmonics are lost by transitioning to the millisecond time scale of pixel acquisition. Hence, information accessible to the operator is severely limited, and its selection is biased by data processing methods. Here we report a fundamentally new approach for dynamic Atomic Force Microscopy imaging based on information-theory analysis of the data stream from the detector. This approach allows full exploration of complex tip-surface interactions, spatial mapping of multidimensional variability of material's properties and their mutual interactions, and imaging at the information channel capacity limit.

Highlights

Scanning probe microscopy has emerged as a primary tool for exploring and controlling the nanoworld
The fundamental component of all force-based dynamic Atomic Force Microscopy (AFM) methods is the nexus between data processing electronics operating at millisecond time scales of pixel acquisition, and the sub-microsecond scale of cantilever oscillations
The choice of information conversion scheme imposes the external observer bias on recorded data, for example, heterodyne detection in classical lock-in (LI) and phaselocked loop processing inevitably restricts physics of tip–surface interactions to purely sinusoidal processes. This limitation is recognized by the AFM community, and numerous techniques based on the detection of higher harmonics[12,13] and full force–distance curve measurements are being introduced to fully capture behaviour of a tip–surface interactions

Summary

Introduction

Scanning probe microscopy has emerged as a primary tool for exploring and controlling the nanoworld. The fundamental component of all force-based dynamic Atomic Force Microscopy (AFM) methods is the nexus between data processing electronics operating at millisecond time scales of pixel acquisition, and the sub-microsecond scale of cantilever oscillations. In such a process, multidimensional dynamic information of a vibrating cantilever is severely compressed to only several measured parameters. We introduce a novel principle for information acquisition and processing in dynamic AFM techniques, further referred to as general mode (G-mode) SPM, based on information–theory analysis of the cantilever output stream This approach is based on full acquisition of the cantilever position data during an experiment and subsequent multivariate statistical analyses of the full trajectory data set, yielding statistically relevant components of response and their spatial variability. This approach allows one to examine and store only statistically relevant components of cantilever response and materials functionality, further enabling the interplay between spatial resolution and noise levels

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