'Big Bang' tomography as a new route to atomic-resolution electron tomography.
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| Title: | 'Big Bang' tomography as a new route to atomic-resolution electron tomography. |
|---|---|
| Authors: | Van Dyck, Dirk, Chen, Fu-Rong |
| Source: | Nature. 6/14/2012, Vol. 486 Issue 7402, p243-246. 4p. 1 Color Photograph, 1 Diagram, 2 Graphs. |
| Subjects: | Big bang theory, Atoms, Tomography, Electron microscopy, Fourier analysis, Wave functions |
| Abstract: | Until now it has not been possible to image at atomic resolution using classical electron tomographic methods, except when the target is a perfectly crystalline nano-object imaged along a few zone axes. The main reasons are that mechanical tilting in an electron microscope with sub-ångström precision over a very large angular range is difficult, that many real-life objects such as dielectric layers in microelectronic devices impose geometrical constraints and that many radiation-sensitive objects such as proteins limit the total electron dose. Hence, there is a need for a new tomographic scheme that is able to deduce three-dimensional information from only one or a few projections. Here we present an electron tomographic method that can be used to determine, from only one viewing direction and with sub-ångström precision, both the position of individual atoms in the plane of observation and their vertical position. The concept is based on the fact that an experimentally reconstructed exit wave consists of the superposition of the spherical waves that have been scattered by the individual atoms of the object. Furthermore, the phase of a Fourier component of a spherical wave increases with the distance of propagation at a known 'phase speed'. If we assume that an atom is a point-like object, the relationship between the phase and the phase speed of each Fourier component is linear, and the distance between the atom and the plane of observation can therefore be determined by linear fitting. This picture has similarities with Big Bang cosmology, in which the Universe expands from a point-like origin such that the distance of any galaxy from the origin is linearly proportional to the speed at which it moves away from the origin (Hubble expansion). The proof of concept of the method has been demonstrated experimentally for graphene with a two-layer structure and it will work optimally for similar layered materials, such as boron nitride and molybdenum disulphide. [ABSTRACT FROM AUTHOR] |
| Copyright of Nature is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Psychology and Behavioral Sciences Collection |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
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| Header | DbId: pbh DbLabel: Psychology and Behavioral Sciences Collection An: 76575571 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: 'Big Bang' tomography as a new route to atomic-resolution electron tomography. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Van+Dyck%2C+Dirk%22">Van Dyck, Dirk</searchLink><br /><searchLink fieldCode="AR" term="%22Chen%2C+Fu-Rong%22">Chen, Fu-Rong</searchLink> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Nature%22">Nature</searchLink>. 6/14/2012, Vol. 486 Issue 7402, p243-246. 4p. 1 Color Photograph, 1 Diagram, 2 Graphs. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Big+bang+theory%22">Big bang theory</searchLink><br /><searchLink fieldCode="DE" term="%22Atoms%22">Atoms</searchLink><br /><searchLink fieldCode="DE" term="%22Tomography%22">Tomography</searchLink><br /><searchLink fieldCode="DE" term="%22Electron+microscopy%22">Electron microscopy</searchLink><br /><searchLink fieldCode="DE" term="%22Fourier+analysis%22">Fourier analysis</searchLink><br /><searchLink fieldCode="DE" term="%22Wave+functions%22">Wave functions</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Until now it has not been possible to image at atomic resolution using classical electron tomographic methods, except when the target is a perfectly crystalline nano-object imaged along a few zone axes. The main reasons are that mechanical tilting in an electron microscope with sub-ångström precision over a very large angular range is difficult, that many real-life objects such as dielectric layers in microelectronic devices impose geometrical constraints and that many radiation-sensitive objects such as proteins limit the total electron dose. Hence, there is a need for a new tomographic scheme that is able to deduce three-dimensional information from only one or a few projections. Here we present an electron tomographic method that can be used to determine, from only one viewing direction and with sub-ångström precision, both the position of individual atoms in the plane of observation and their vertical position. The concept is based on the fact that an experimentally reconstructed exit wave consists of the superposition of the spherical waves that have been scattered by the individual atoms of the object. Furthermore, the phase of a Fourier component of a spherical wave increases with the distance of propagation at a known 'phase speed'. If we assume that an atom is a point-like object, the relationship between the phase and the phase speed of each Fourier component is linear, and the distance between the atom and the plane of observation can therefore be determined by linear fitting. This picture has similarities with Big Bang cosmology, in which the Universe expands from a point-like origin such that the distance of any galaxy from the origin is linearly proportional to the speed at which it moves away from the origin (Hubble expansion). The proof of concept of the method has been demonstrated experimentally for graphene with a two-layer structure and it will work optimally for similar layered materials, such as boron nitride and molybdenum disulphide. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Nature is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1038/nature11074 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 4 StartPage: 243 Subjects: – SubjectFull: Big bang theory Type: general – SubjectFull: Atoms Type: general – SubjectFull: Tomography Type: general – SubjectFull: Electron microscopy Type: general – SubjectFull: Fourier analysis Type: general – SubjectFull: Wave functions Type: general Titles: – TitleFull: 'Big Bang' tomography as a new route to atomic-resolution electron tomography. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Van Dyck, Dirk – PersonEntity: Name: NameFull: Chen, Fu-Rong IsPartOfRelationships: – BibEntity: Dates: – D: 14 M: 06 Text: 6/14/2012 Type: published Y: 2012 Identifiers: – Type: issn-print Value: 00280836 Numbering: – Type: volume Value: 486 – Type: issue Value: 7402 Titles: – TitleFull: Nature Type: main |
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