The Experts below are selected from a list of 37611 Experts worldwide ranked by ideXlab platform
Sergei V. Kalinin - One of the best experts on this subject based on the ideXlab platform.
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feature extraction via similarity search application to atom finding and denoising in electron and Scanning Probe Microscopy imaging
Advanced Structural and Chemical Imaging, 2018Co-Authors: Suhas Somnath, Sergei V. Kalinin, Chris Smith, Albina Y Borisevich, Nicholas Cross, Gerd Duscher, Stephen JesseAbstract:We develop an algorithm for feature extraction based on structural similarity and demonstrate its application for atom and pattern finding in high-resolution electron and Scanning Probe Microscopy images. The use of the combined local identifiers formed from an image subset and appended Fourier, or other transform, allows tuning selectivity to specific patterns based on the nature of the recognition task. The proposed algorithm is implemented in Pycroscopy, a community-driven scientific data analysis package, and is accessible through an interactive Jupyter notebook available on GitHub.
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big deep and smart data in Scanning Probe Microscopy
ACS Nano, 2016Co-Authors: Sergei V. Kalinin, Evgheni Strelcov, Alex Belianinov, Suhas Somnath, Rama K Vasudevan, Eric J Lingerfelt, Rick Archibald, Chaomei Chen, Roger Proksch, Nouamane LaanaitAbstract:Scanning Probe Microscopy (SPM) techniques have opened the door to nanoscience and nanotechnology by enabling imaging and manipulation of the structure and functionality of matter at nanometer and atomic scales. Here, we analyze the scientific discovery process in SPM by following the information flow from the tip–surface junction, to knowledge adoption by the wider scientific community. We further discuss the challenges and opportunities offered by merging SPM with advanced data mining, visual analytics, and knowledge discovery technologies.
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band excitation in Scanning Probe Microscopy recognition and functional imaging
ChemInform, 2014Co-Authors: Stephen Jesse, Evgheni Strelcov, Alex Belianinov, Rama K Vasudevan, Roger Proksch, Liam Collins, M B Okatan, Arthur P Baddorf, Sergei V. KalininAbstract:Field confinement at the junction between a biased Scanning Probe microscope's tip and solid surface enables local probing of various bias-induced transformations, such as polarization switching, ionic motion, and electrochemical reactions. The nanoscale size of the biased region, smaller or comparable to that of features such as grain boundaries and dislocations, potentially allows for the study of kinetics and thermodynamics at the level of a single defect. In contrast to classical statistically averaged approaches, this approach allows one to link structure to functionality and deterministically decipher associated mesoscopic and atomistic mechanisms. Furthermore, responses measured as a function of frequency and bias can serve as a fingerprint of local material functionality, allowing for local recognition imaging of inorganic and biological systems. This article reviews current progress in multidimensional Scanning Probe Microscopy techniques based on band excitation time and voltage spectroscopies, including discussions on data acquisition, dimensionality reduction, and visualization, along with future challenges and opportunities for the field.
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band excitation in Scanning Probe Microscopy sines of change
Journal of Physics D, 2011Co-Authors: Stephen Jesse, Sergei V. KalininAbstract:In the three decades since Scanning Probe Microscopy (SPM) methods have entered the scientific arena, they have become one of the main tools of nanoscale science and technology by offering the capability for imaging topography, magnetic, electrical and mechanical properties on the nanometre scale. The vast majority of force-based SPM techniques to date are based on single-frequency sinusoidal excitation and detection. Here, we illustrate the intrinsic limitations of single-frequency detection that stem from the fundamental physics of dynamic systems. Consequently, many aspects of nanoscale materials functionality including quantitative mechanical, magnetic and electrical measurements, as well as probing dissipative interactions, remain unexplored. Band excitation is illustrated as a universal alternative to traditional single-frequency techniques that allows quantitative and reliable studies of dissipative and conservative phenomena, and can be universally applied to all ambient and liquid SPM methods.
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Piezoelectric indentation of a flat circular punch accompanied by frictional sliding and applications to Scanning Probe Microscopy
International Journal of Engineering Science, 2009Co-Authors: Arty Makagon, Mark Kachanov, Edgar Karapetian, Sergei V. KalininAbstract:Indentation of a piezoelectric half-space by a flat circular indenter accompanied by frictional sliding is considered. Full-field electroelastic solutions in elementary functions are obtained. The solution is based on the correspondence principle between elastic and piezoelectric problems. Stiffness relations between applied load and resulting displacement are given in elementary functions. In conjunction with the conical and spherical solutions, given previously by Makagon et al. [A. Makagon, M. Kachanov, S.V. Kalinin, E. Karapetian, Indentation and frictional sliding of spherical and conical punches into piezoelectric half-space, Physical Review B 76 (2007) 064115 (14)], this work completes the set of limiting cases of tip geometries utilized in lateral force Microscopy (LFM) technology. Implications for quantitative interpretation of Scanning Probe Microscopy (SPM) data and tribological data are analyzed.
Robert A. Wolkow - One of the best experts on this subject based on the ideXlab platform.
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autonomous Scanning Probe Microscopy in situ tip conditioning through machine learning
ACS Nano, 2018Co-Authors: Mohammad Rashidi, Robert A. WolkowAbstract:Atomic-scale characterization and manipulation with Scanning Probe Microscopy rely upon the use of an atomically sharp Probe. Here we present automated methods based on machine learning to automatically detect and recondition the quality of the Probe of a Scanning tunneling microscope. As a model system, we employ these techniques on the technologically relevant hydrogen-terminated silicon surface, training the network to recognize abnormalities in the appearance of surface dangling bonds. Of the machine learning methods tested, a convolutional neural network yielded the greatest accuracy, achieving a positive identification of degraded tips in 97% of the test cases. By using multiple points of comparison and majority voting, the accuracy of the method is improved beyond 99%.
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Autonomous Scanning Probe Microscopy in Situ Tip Conditioning through Machine Learning
ACS Nano, 2018Co-Authors: Mohammad Rashidi, Robert A. WolkowAbstract:Atomic scale characterization and manipulation with Scanning Probe Microscopy rely upon the use of an atomically sharp Probe. Here we present automated methods based on machine learning to automatically detect and recondition the quality of the Probe of a Scanning tunneling microscope. As a model system, we employ these techniques on the technologically relevant hydrogen-terminated silicon surface, training the network to recognize abnormalities in the appearance of surface dangling bonds. Of the machine learning methods tested, a convolutional neural network yielded the greatest accuracy, achieving a positive identification of degraded tips in 97% of the test cases. By using multiple points of comparison and majority voting, the accuracy of the method is improved beyond 99%. The methods described here can easily be generalized to other material systems and nanoscale imaging techniques.
Peter Liljeroth - One of the best experts on this subject based on the ideXlab platform.
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single molecule chemistry and physics explored by low temperature Scanning Probe Microscopy
Chemical Communications, 2011Co-Authors: Ingmar Swart, Leo Gross, Peter LiljerothAbstract:It is well known that Scanning Probe techniques such as Scanning tunnelling Microscopy (STM) and atomic force Microscopy (AFM) routinely offer atomic scale information on the geometric and the electronic structure of solids. Recent developments in STM and especially in non-contact AFM have allowed imaging and spectroscopy of individual molecules on surfaces with unprecedented spatial resolution, which makes it possible to study chemistry and physics at the single molecule level. In this feature article, we first review the physical concepts underlying image contrast in STM and AFM. We then focus on the key experimental considerations and use selected examples to demonstrate the capabilities of modern day low-temperature Scanning Probe Microscopy in providing chemical insight at the single molecule level.
Leo Gross - One of the best experts on this subject based on the ideXlab platform.
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single molecule chemistry and physics explored by low temperature Scanning Probe Microscopy
Chemical Communications, 2011Co-Authors: Ingmar Swart, Leo Gross, Peter LiljerothAbstract:It is well known that Scanning Probe techniques such as Scanning tunnelling Microscopy (STM) and atomic force Microscopy (AFM) routinely offer atomic scale information on the geometric and the electronic structure of solids. Recent developments in STM and especially in non-contact AFM have allowed imaging and spectroscopy of individual molecules on surfaces with unprecedented spatial resolution, which makes it possible to study chemistry and physics at the single molecule level. In this feature article, we first review the physical concepts underlying image contrast in STM and AFM. We then focus on the key experimental considerations and use selected examples to demonstrate the capabilities of modern day low-temperature Scanning Probe Microscopy in providing chemical insight at the single molecule level.
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recent advances in submolecular resolution with Scanning Probe Microscopy
Nature Chemistry, 2011Co-Authors: Leo GrossAbstract:It has been a long-standing goal to image individual organic molecules with atomic resolution. Although atomic resolution is routinely obtained on many crystalline surfaces by Scanning Probe Microscopy (SPM) methods, clear atomic resolution on molecules has only been achieved in the past two years by means of non-contact atomic force Microscopy (NC-AFM) 1,2 and Scanning tunnelling hydrogen Microscopy (STHM) 3–5 . In these recent works aromatic molecules were imaged, and for the first time the individual atoms within the molecules were resolved. The obtained images directly visualize the molecular structure, for example, showing hexagons at the position of six-membered carbon rings. For both techniques, NC-AFM and STHM, an atomic functionalization of the sensor (that is, the placing of a well-defined atom or molecule at the tip of the Scanning Probe) was the key for achieving enhanced resolution. In the case of atomic force Microscopy (AFM), the tip was modified by deliberately picking up a single carbon monoxide mol ecule, whereas in the case of STHM, the resolution was increased after bringing molecular hydrogen into the gap between the tip and the sample. Both techniques produce high-resolution images that closely resemble the molecular structure. This improved resolution has immediately proved useful for applications to identify the molecular structure of natural compounds 2
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Organic structure determination using atomic-resolution Scanning Probe Microscopy
Nature Chemistry, 2010Co-Authors: Leo Gross, Fabian Mohn, Nikolaj Moll, Gerhard Meyer, Rainer Ebel, Wael M. Abdel-mageed, Marcel JasparsAbstract:Nature offers a huge and only partially explored variety of small molecules with potential pharmaceutical applications. Commonly used characterization methods for natural products include spectroscopic techniques such as nuclear magnetic resonance spectroscopy and mass spectrometry. In some cases, however, these techniques do not succeed in the unambiguous determination of the chemical structure of unknown compounds. To validate the usefulness of Scanning Probe Microscopy as an adjunct to the other tools available for organic structure analysis, we used the natural product cephalandole A, which had previously been misassigned, and later corrected. Our results, corroborated by density functional theory, demonstrate that direct imaging of an organic compound with atomic-resolution force Microscopy facilitates the accurate determination of its chemical structure. We anticipate that our method may be developed further towards molecular imaging with chemical sensitivity, and will become generally useful in solving certain classes of natural product structures. The structure of many natural products can often only be confirmed by comparison with a synthetic sample. Here, Scanning Probe Microscopy techniques allow the ultimate discrimination between structures suggested by the standard range of analytical techniques, proving the power of single-molecule imaging for molecular structure determination.
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organic structure determination using atomic resolution Scanning Probe Microscopy
Nature Chemistry, 2010Co-Authors: Leo Gross, Fabian Mohn, Nikolaj Moll, Gerhard Meyer, Rainer Ebel, Wael M Abdelmageed, Marcel JasparsAbstract:Nature offers a huge and only partially explored variety of small molecules with potential pharmaceutical applications. Commonly used characterization methods for natural products include spectroscopic techniques such as nuclear magnetic resonance spectroscopy and mass spectrometry. In some cases, however, these techniques do not succeed in the unambiguous determination of the chemical structure of unknown compounds. To validate the usefulness of Scanning Probe Microscopy as an adjunct to the other tools available for organic structure analysis, we used the natural product cephalandole A, which had previously been misassigned, and later corrected. Our results, corroborated by density functional theory, demonstrate that direct imaging of an organic compound with atomic-resolution force Microscopy facilitates the accurate determination of its chemical structure. We anticipate that our method may be developed further towards molecular imaging with chemical sensitivity, and will become generally useful in solving certain classes of natural product structures.
Gabino Rubio-bollinger - One of the best experts on this subject based on the ideXlab platform.
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Dynamics of quartz tuning fork force sensors used in Scanning Probe Microscopy
Nanotechnology, 2009Co-Authors: Andres Castellanos-gomez, Nicolás Agraït, Gabino Rubio-bollingerAbstract:We have performed an experimental characterization of the dynamics of oscillating quartz tuning forks which are being increasingly used in Scanning Probe Microscopy as force sensors. We show that tuning forks can be described as a system of coupled oscillators. Nevertheless, this description requires knowledge of the elastic coupling constant between the prongs of the tuning fork, which has not yet been measured. Therefore, tuning forks have usually been described within the single oscillator or the weakly coupled oscillators approximation that neglects the coupling between the prongs. We propose three different procedures to measure the elastic coupling constant: an opto-mechanical method, a variation of the Cleveland method and a thermal noise based method. We find that the coupling between the quartz tuning fork prongs has a strong influence on the dynamics and the measured motion is in remarkable agreement with a simple model of coupled harmonic oscillators. The precise determination of the elastic coupling between the prongs of a tuning fork allows us to obtain a quantitative relation between the resonance frequency shift and the force gradient acting at the free end of a tuning fork prong.
