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Flexible 2D Crystals of Polycyclic Aromatics Stabilized by Static Distortion Waves
[Image: see text] The epitaxy of many organic films on inorganic substrates can be classified within the framework of rigid lattices which helps to understand the origin of energy gain driving the epitaxy of the films. Yet, there are adsorbate–substrate combinations with distinct mutual orientations...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American
Chemical Society
2016
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4963923/ https://www.ncbi.nlm.nih.gov/pubmed/27014920 http://dx.doi.org/10.1021/acsnano.6b00935 |
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author | Meissner, Matthias Sojka, Falko Matthes, Lars Bechstedt, Friedhelm Feng, Xinliang Müllen, Klaus Mannsfeld, Stefan C. B. Forker, Roman Fritz, Torsten |
author_facet | Meissner, Matthias Sojka, Falko Matthes, Lars Bechstedt, Friedhelm Feng, Xinliang Müllen, Klaus Mannsfeld, Stefan C. B. Forker, Roman Fritz, Torsten |
author_sort | Meissner, Matthias |
collection | PubMed |
description | [Image: see text] The epitaxy of many organic films on inorganic substrates can be classified within the framework of rigid lattices which helps to understand the origin of energy gain driving the epitaxy of the films. Yet, there are adsorbate–substrate combinations with distinct mutual orientations for which this classification fails and epitaxy cannot be explained within a rigid lattice concept. It has been proposed that tiny shifts in atomic positions away from ideal lattice points, so-called static distortion waves (SDWs), are responsible for the observed orientational epitaxy in such cases. Using low-energy electron diffraction and scanning tunneling microscopy, we provide direct experimental evidence for SDWs in organic adsorbate films, namely hexa-peri-hexabenzocoronene on graphite. They manifest as wave-like sub-Ångström molecular displacements away from an ideal adsorbate lattice which is incommensurate with graphite. By means of a density-functional-theory based model, we show that, due to the flexibility in the adsorbate layer, molecule–substrate energy is gained by straining the intermolecular bonds and that the resulting total energy is minimal for the observed domain orientation, constituting the orientational epitaxy. While structural relaxation at an interface is a common assumption, the combination of the precise determination of the incommensurate epitaxial relation, the direct observation of SDWs in real space, and their identification as the sole source of epitaxial energy gain constitutes a comprehensive proof of this effect. |
format | Online Article Text |
id | pubmed-4963923 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | American
Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-49639232016-07-29 Flexible 2D Crystals of Polycyclic Aromatics Stabilized by Static Distortion Waves Meissner, Matthias Sojka, Falko Matthes, Lars Bechstedt, Friedhelm Feng, Xinliang Müllen, Klaus Mannsfeld, Stefan C. B. Forker, Roman Fritz, Torsten ACS Nano [Image: see text] The epitaxy of many organic films on inorganic substrates can be classified within the framework of rigid lattices which helps to understand the origin of energy gain driving the epitaxy of the films. Yet, there are adsorbate–substrate combinations with distinct mutual orientations for which this classification fails and epitaxy cannot be explained within a rigid lattice concept. It has been proposed that tiny shifts in atomic positions away from ideal lattice points, so-called static distortion waves (SDWs), are responsible for the observed orientational epitaxy in such cases. Using low-energy electron diffraction and scanning tunneling microscopy, we provide direct experimental evidence for SDWs in organic adsorbate films, namely hexa-peri-hexabenzocoronene on graphite. They manifest as wave-like sub-Ångström molecular displacements away from an ideal adsorbate lattice which is incommensurate with graphite. By means of a density-functional-theory based model, we show that, due to the flexibility in the adsorbate layer, molecule–substrate energy is gained by straining the intermolecular bonds and that the resulting total energy is minimal for the observed domain orientation, constituting the orientational epitaxy. While structural relaxation at an interface is a common assumption, the combination of the precise determination of the incommensurate epitaxial relation, the direct observation of SDWs in real space, and their identification as the sole source of epitaxial energy gain constitutes a comprehensive proof of this effect. American Chemical Society 2016-03-25 2016-07-26 /pmc/articles/PMC4963923/ /pubmed/27014920 http://dx.doi.org/10.1021/acsnano.6b00935 Text en Copyright © 2016 American Chemical Society This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
spellingShingle | Meissner, Matthias Sojka, Falko Matthes, Lars Bechstedt, Friedhelm Feng, Xinliang Müllen, Klaus Mannsfeld, Stefan C. B. Forker, Roman Fritz, Torsten Flexible 2D Crystals of Polycyclic Aromatics Stabilized by Static Distortion Waves |
title | Flexible
2D Crystals of Polycyclic Aromatics Stabilized
by Static Distortion Waves |
title_full | Flexible
2D Crystals of Polycyclic Aromatics Stabilized
by Static Distortion Waves |
title_fullStr | Flexible
2D Crystals of Polycyclic Aromatics Stabilized
by Static Distortion Waves |
title_full_unstemmed | Flexible
2D Crystals of Polycyclic Aromatics Stabilized
by Static Distortion Waves |
title_short | Flexible
2D Crystals of Polycyclic Aromatics Stabilized
by Static Distortion Waves |
title_sort | flexible
2d crystals of polycyclic aromatics stabilized
by static distortion waves |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4963923/ https://www.ncbi.nlm.nih.gov/pubmed/27014920 http://dx.doi.org/10.1021/acsnano.6b00935 |
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