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dc.contributor.author
Juraschek, Dominik M.
dc.contributor.supervisor
Spaldin, Nicola
dc.contributor.supervisor
Gambardella, Pietro
dc.contributor.supervisor
Johnson, Steven L.
dc.date.accessioned
2019-01-14T11:57:14Z
dc.date.available
2019-01-14T10:53:23Z
dc.date.available
2019-01-14T11:57:14Z
dc.date.issued
2018-12-13
dc.identifier.uri
http://hdl.handle.net/20.500.11850/315499
dc.identifier.doi
10.3929/ethz-b-000315499
dc.description.abstract
In my thesis, I have strengthened the understanding of the vibrational dynamics of materials in response to stimulation by intense laser pulses. Vibrations of the crystal structure can be used to manipulate a material's properties in the electronic ground state on timescales less than a picosecond by changing the average ionic lattice that the electrons experience. In order to leverage this technique, the quantized vibrations of the lattice, called optical phonons, have to be excited coherently by intense pulses in the terahertz and mid-infrared spectral region. Excitation mechanisms for optical phonons have been investigated theoretically on a phenomenological level for several decades, but due to the high computational costs, a quantitative description within the density functional theory framework has only become possible in recent years. I further developed and used this toolkit to explain experimental discoveries that were not previously understood and to predict new phenomena arising from coherent optical phonon excitation. Here, I present three major research projects that I have completed on this topic: In the first project, I proposed a novel nonlinear phonon coupling mechanism that enhances the controllability over structural distortions induced in the crystal lattice. In the second project, I created a general framework that captures the different stimulated Raman scattering mechanisms for the excitation of Raman-active phonons in insulators. In particular, I proposed a novel scattering mechanism that significantly increases the efficiency of the excitation over established methods. In the third project I showed that magnetism arises from temporally varying electric polarization. I have demonstrated this phenomenon with the example of circularly polarized phonons that produce a magnetic moment, which interacts with an external magnetic field or the magnetic order of the material itself. I conclude the thesis by giving a perspective for future research directions. I suggest that new discoveries in the field will be led by experiments carried out at free-electron laser facilities and by developments in the first-principles description of coupled electron- and spin-phonon dynamics. Understanding the time-dependent physics of phonons may in turn lead to new paradigms in designing materials with greater functionality in the static case.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
ETH Zurich
en_US
dc.rights.uri
http://rightsstatements.org/page/InC-NC/1.0/
dc.subject
Nonlinear phononics
en_US
dc.subject
Terahertz
en_US
dc.subject
Multiferroics
en_US
dc.title
Coherent Optical Phononics
en_US
dc.type
Doctoral Thesis
dc.rights.license
In Copyright - Non-Commercial Use Permitted
ethz.size
86 p.
en_US
ethz.code.ddc
DDC - DDC::6 - Technology, medicine and applied sciences::620 - Engineering & allied operations
ethz.code.ddc
DDC - DDC::5 - Science::530 - Physics
ethz.identifier.diss
25620
en_US
ethz.publication.place
Zurich
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02160 - Dep. Materialwissenschaft / Dep. of Materials::03903 - Spaldin, Nicola A. / Spaldin, Nicola A.
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02160 - Dep. Materialwissenschaft / Dep. of Materials::03903 - Spaldin, Nicola A. / Spaldin, Nicola A.
en_US
ethz.relation.isCompiledBy
20.500.11850/128822
ethz.relation.isCompiledBy
20.500.11850/209708
ethz.relation.isCompiledBy
20.500.11850/190352
ethz.relation.isCompiledBy
20.500.11850/267638
ethz.date.deposited
2019-01-14T10:53:40Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2019-01-14T11:58:12Z
ethz.rosetta.lastUpdated
2021-02-15T03:18:09Z
ethz.rosetta.versionExported
true
ethz.COinS
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