scholarly journals Strain Characterization in Two-Dimensional Crystals

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4460
Author(s):  
Shizhe Feng ◽  
Zhiping Xu

Two-dimensional (2D) crystals provides a material platform to explore the physics and chemistry at the single-atom scale, where surface characterization techniques can be applied straightforwardly. Recently there have been emerging interests in engineering materials through structural deformation or transformation. The strain field offers crucial information of lattice distortion and phase transformation in the native state or under external perturbation. Example problems with significance in science and engineering include the role of defects and dislocations in modulating material behaviors, and the process of fracture, where remarkable strain is built up in a local region, leading to the breakdown of materials. Strain is well defined in the continuum limit to measure the deformation, which can be alternatively calculated from the arrangement of atoms in discrete lattices through methods such as geometrical phase analysis from transmission electron imaging, bond distortion or virial stress from atomic structures obtained from molecular simulations. In this paper, we assess the accuracy of these methods in quantifying the strain field in 2D crystals through a number of examples, with a focus on their localized features at material imperfections. The sources of errors are discussed, providing a reference for reliable strain mapping.

Author(s):  
Koenraad G F Janssens ◽  
Omer Van der Biest ◽  
Jan Vanhellemont ◽  
Herman E Maes ◽  
Robert Hull

There is a growing need for elastic strain characterization techniques with submicrometer resolution in several engineering technologies. In advanced material science and engineering the quantitative knowledge of elastic strain, e.g. at small particles or fibers in reinforced composite materials, can lead to a better understanding of the underlying physical mechanisms and thus to an optimization of material production processes. In advanced semiconductor processing and technology, the current size of micro-electronic devices requires an increasing effort in the analysis and characterization of localized strain. More than 30 years have passed since electron diffraction contrast imaging (EDCI) was used for the first time to analyse the local strain field in and around small coherent precipitates1. In later stages the same technique was used to identify straight dislocations by simulating the EDCI contrast resulting from the strain field of a dislocation and comparing it with experimental observations. Since then the technique was developed further by a small number of researchers, most of whom programmed their own dedicated algorithms to solve the problem of EDCI image simulation for the particular problem they were studying at the time.


Author(s):  
Jeffry A. Reidler ◽  
John P. Robinson

We have prepared two-dimensional (2D) crystals of tetanus toxin using procedures developed by Uzgiris and Kornberg for the directed production of 2D crystals of monoclonal antibodies at an antigen-phospholipid monolayer interface. The tetanus toxin crystals were formed using a small mole fraction of the natural receptor, GT1, incorporated into phosphatidyl choline monolayers. The crystals formed at low concentration overnight. Two dimensional crystals of this type are particularly useful for structure determination using electron microscopy and computer image refinement. Three dimensional (3D) structural information can be derived from these crystals by computer reconstruction of photographs of toxin crystals taken at different tilt angles. Such 3D reconstructions may help elucidate the mechanism of entry of the enzymatic subunit of toxins into cells, particularly since these crystals form directly on a membrane interface at similar concentrations of ganglioside GT1 to the natural cellular receptors.


2021 ◽  
Vol 23 (14) ◽  
pp. 8784-8791
Author(s):  
Qingling Meng ◽  
Ling Zhang ◽  
Jinge Wu ◽  
Shuwei Zhai ◽  
Xiamin Hao ◽  
...  

Theoretical screening of transition metal atoms anchored on monolayer C9N4 as highly stable, catalytically active and selective single-atom catalysts for nitrogen fixation.


Nanoscale ◽  
2015 ◽  
Vol 7 (16) ◽  
pp. 7402-7408 ◽  
Author(s):  
Long Yuan ◽  
Libai Huang

We systematically investigate the exciton dynamics in monolayered, bilayered, and trilayered WS2 two-dimensional (2D) crystals by time-resolved photoluminescence (TRPL) spectroscopy.


2022 ◽  
Author(s):  
Huixin Ma ◽  
Daijie Deng ◽  
Honghui Zhang ◽  
Feng Chen ◽  
Junchao Qian ◽  
...  

Nitrogen-coordinated single-atom manganese in multi-dimensional nitrogen-doped carbon electrocatalysts (Mn-NC) was successful constructed by combing two-dimensional nanosheets and one-dimensional nanofibers. The Mn-NC exhibited excellent oxygen reduction reaction catalytic activity with half-wave...


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