Project

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Periodic strain fields in graphene and hexagonal boron-nitride on transition metal substrates

Applicant Willmott Philip
Number 150017
Funding scheme Project funding (Div. I-III)
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Condensed Matter Physics
Start/End 01.02.2014 - 31.01.2015
Approved amount 54'240.00
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Keywords (5)

graphene; surface x-ray diffraction; synchrotron radiation; nanomesh; interfacial physics

Lay Summary (German)

Lead
When an atomic layer of hexagonal boron-nitride (hBN) is deposited on the surface of rhodium, the hBN forms a structure reminiscent of chicken wire, with a periodicity of approximately 30 Angstrom. This so-called "nanomesh" can trap clusters or molecules in the hexagonal holes bordered by the nanomesh "wires". In this project, the prototypical system of Xe-clusters will be deposited on the nanomesh and their atomic structure investigated with synchrotron-based surface x-ray diffraction.
Lay summary

Das hBN/Rh(111)-System wird verwendet, um Xe bei kryogenischen Temperaturen zu deponieren. Fruehere Arbeit hat gezeigt, das wohldefinierte Strukturen gebildet werden koennen wenn man zuerst mehrere Monolagern Xe deponiert und danach das System langsam und kontrolliert aufwaermt bis etwa 77 K. Zuerst werden all die Xe ausser die letzte Monolage desorbiert und dan werden isolierte Klustern in den Nanomesh-Loechern gebildet. Letzlich werden Ringen von Xe an den Raendern den Nanomesh-Hexagons gebildet, wo die Absorptionsenergie am groessten ist. Nachdem das Prozedur identifiziert ist, wie man solche Ringe zuverlaessig produzieren kann, werden diese mittels Oberflaechen Roentgenbeugung untersucht werden, um die atomare Struktur mit sub-Angstrom-Aufloesung zu bestimmen.

Xe/hBN/Rh ist eine prototypische System, die ausgewahlt wurde aus zwei Hauptgrunden: (a) Fruehere Experimente haben gezeigt, dass solche Xe-Ringe relative problemlos sythetiziert werden koennen; und (b) das Xe kann einfach vollstaendig desorbiert werden, in dem man auf etwa 100 K aufheizt. Dabei kann man mehrere Experimente augefuehrt werden, ohne dass man bei jedem neuen Versuch, die Nanomesh wiederholt praepaerieren muss. Das "Knowhow" gewonnen durch diese Experimente werden in zukunftigen Projekten verwendet werden, um Anordnungen von komplexeren, organischen- und biologischen Molekuelen zu untersuchen, vorallem die, die man schlecht in der Form von makroskopischen Kristallen produzieren kann.

 

Direct link to Lay Summary Last update: 26.09.2013

Responsible applicant and co-applicants

Employees

Name Institute

Collaboration

Group / person Country
Types of collaboration
Prof. Dr. Juerg Hutter/Physical Chemistry Institute, University of Zuerich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. Dr. Herbert Over/Physical Chemistry Institute, University of Giessen Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. Dr. Hongjun Gao/IOP CAS Beijing China (Asia)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Dr. Marcella Iannuzzi, Physical Chemistry Institute, University of Zuerich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Associated projects

Number Title Start Funding scheme
122703 Boron nitride nanomesh as a template for guided self-assembly of molecular arrays 01.10.2008 Sinergia
132509 Periodic strain fields in graphene and hexagonal boron-nitride on transition metal substrates 01.02.2011 Project funding (Div. I-III)
124691 Spin physics and electron dynamics at surfaces, interfaces and in ordered molecular layers 01.04.2009 Project funding (Div. I-III)

Abstract

This document describes a research proposal for funding by the Swiss National Science Foundation for an extension to a fourth year of the PhD project 200021-132509 “Periodic strain fields in graphene and h-BN on transition-metal surfaces”, carried out by Mr. Irakli Kalichava, within the Surface Diffraction group of the Materials Science beamline of the Swiss Light Source, Paul Scherrer Institut. The PhD program began on 15th January, 2011, and has progressed satisfactorily to date. Four subprojects have been pursued. Two have produced high-quality and original results, presently being written up for publication. The other two unfortunately proved to be unsuccessful. This was through no fault of the PhD student, but was merely a fact of nature.The project is concerned with the investigation of the atomic structure and physical properties of single layers of graphene and hexagonal boron nitride (h-BN) grown on single-crystal transition metal surfaces. Particular emphasis has been on the experimental determination of the strain fields, i.e., the deviation of the atomic coordinates from a non-interacting, single-layer-substrate system, plus comparative studies with highly complex density functional theory (DFT) calculations, in a collaborative project.In the final part of the PhD, the ordered decoration of the nanomesh h-BN/Rh(111) with xenon atoms/clusters will be investigated in-situ using surface x-ray diffraction. This will serve as a prototypical system for future studies of regular nanoarrays of more complex species, in particular macromolecules and metallorganics. By depositing submonolayer doses of Xe on h-BN/Rh(111) at low temperatures, using our newly commissioned in-situ cryochamber, repeated measurements using the same template can be performed by simple heating/colling cycles. It is hoped that the knowledge gained here will be beneficial in future controlled nanoarray assemblages of, for example, membrane proteins, for studies using both synchrotron light and XFEL radiation.
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