University of Oulu

Extended and finite graphenes : computational studies of magnetic resonance and magneto-optic properties

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Author: Vähäkangas, Jarkko
Organizations: University of Oulu, Faculty of Science, Physics
Format: ebook
Online Access: PDF Full Text (PDF, 6.9 MB)
Persistent link: http://urn.fi/urn:isbn:9789526208619
Language: English
Published: 2015
Publish Date: 2016-11-11
Thesis type: Doctoral Dissertation
Defence Note: Academic dissertation to be presented with the assent of the Doctoral Training Committee of Technology and Natural Sciences of the University of Oulu for public discussion in the Auditorium L10, Linnanmaa, on August 20th 2015, at 12 o’clock noon.
Reviewer: Professor Chiara Cappelli
Professor Antti Karttunen
Opponent: Professor Oleg Yazyev
Kustos: Professor Juha Vaara
Description:

Abstract

In this thesis, the magnetic resonance and magneto-optical rotation parameters are studied in single-layer carbon systems of two different dimensionalities. Based on electronic structure calculations, the spectral parameters are predicted for both extended (2D) and finite, molecular (0D) systems consisting of pure sp²-hybridised pristine graphene (G), as well as hydrogenated and fluorinated, sp³-hybridised graphene derivatives, graphane (HG) and fluorographene (FG), respectively.

Nuclear magnetic resonance (NMR) parameters are calculated for G, HG and FG systems at their large-system limit. For their 0D counterparts, graphene flakes, qualitative spectral trends are predicted as functions of their size and perimeter type. The last group of studied carbon systems consists of 2D graphenes containing spin-1/2 paramagnetic defects. Electron spin resonance (ESR) parameters and paramagnetic NMR shieldings are predicted for four different paramagnetic systems, including the vacancy-defected graphane and fluorographene, as well as graphene with hydrogen and fluorine adatoms. The magneto-optic properties of G and HG flakes are studied in terms of Faraday optical rotation and nuclear spin optical rotation parameters, to investigate the effects of their finite size and also the different level of hydrogenation.

All the different investigated parameters displayed characteristic sensitivity to the electronic and atomic structure of the studied graphenes. The parameters obtained provide an insight into the physics of these 0D and 2D carbon materials, and encourage experimental verification.


Series: Report series in physical sciences
ISSN: 1239-4327
ISSN-L: 1239-4327
ISBN: 978-952-62-0861-9
ISBN Print: 978-951-42-0860-2
Issue: 97
Subjects:
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