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Hobbs, Sarah. "Development of resonant inelastic X-ray scattering spectroscopy". Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/349475/.
Kvashnina, Kristina. "Resonant Inelastic X-ray Scattering of Rare-Earth and Copper Systems". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7094.
Geondzhian, Andrey. "Resonant inelastic X-ray scattering as a probe of exciton-phonon coupling". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAY077/document.
Phonons contribute to resonant inelastic X-ray scattering (RIXS) as a consequence of the coupling between electronic and lattice degrees of freedom. Unlike other techniques that are sensitive to electron-phonon interactions, RIXS can give access to momentum dependent coupling constants. Information about the dispersion of the electron-phonon interaction is highly desirable in the context of understanding anisotropic conventional and unconventional superconductivity.We considered the phonon contribution to RIXS from the theoretical point of view. In contrast to previous studies, we emphasize the role of the core-hole lattice coupling. Our model, with parameters obtained from first principles, shows that even in the case of a deep core-hole, RIXS probes exciton-phonon coupling rather than a direct electron-phonon coupling.This difference leads to quantitative and qualitative deviations from the interpretation of the implied electron-phonon coupling from the standard view expressed in the literature. Thus, our objective is to develop a rigorous approach to quantify electron-phonon coupling within the context of RIXS measurements. The ability to accurately reproduce experimental results from first-principles calculations, without recourse to adjustable parameters, should be viewed as the ultimate test of a proper understanding of the phonon contribution to RIXS.We start by considering only the core-hole--phonon interaction within the context of X-ray photoemission spectroscopy. We combine an ab initio calculation of the real-space response function with many-body Green's functions techniques to reproduce the vibrational side-bands in SiX4 (X=H, F) molecules. The approach we developed is suitable for application to crystalline materials.We next consider the phonon contribution to X-ray absorption spectra. Unlike the charged excitations generated by X-ray photoemission, X-ray absorption creates a neutral excitation that we approximate as a core-hole and an excited electron. We first solved the electronic part of the problem on the level of the Bethe-Salpeter equation and then dressed the resulting 2-particle excitonic quasiparticle with the exciton-phonon interactions using the cumulant ansatz. The viability of this methodology was tested by calculating the N K-edge XAS of the N2 molecule and the O K-edge of acetone. The resulting vibronic spectra agreed favorably with experimental results.Finally, we construct a hybrid formulation of the RIXS cross section that preserves explicit summation over a small number of final states, but replaces the summation over intermediate states, which might be enormously expensive, with a Green's function. We develop an expansion of the Green's function and derive both analytically exact (in the no-recoil limit) and approximate solutions. The formalism was again tested on the O K-edge of acetone and agrees well with the experiment. To provide an outlook towards future work, we discuss application of the developed formalism to crystalline materials
Marra, Pasquale. "Theoretical approach to Direct Resonant Inelastic X-Ray Scattering on Magnets and Superconductors". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-185619.
Balandeh, Shadi. "X-ray absorption and resonant inelastic X-ray scattering calculations with ligand field single cluster method on praseodymium nickel oxide". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45392.
Scherer, Ricardo [Verfasser]. "Soft X-ray emission and resonant inelastic scattering study of polycyclic hydrocarbons / Ricardo Scherer". München : GRIN Verlag, 2019. http://d-nb.info/1193574277/34.
Thomas, Rowena. "Development of resonant inelastic X-ray metal catalysts scattering spectroscopy for 4d and 5d transition metal catalysts". Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/354566/.
Schmitt, Thorsten. "Resonant Soft X-Ray Emission Spectroscopy of Vanadium Oxides and Related Compounds". Doctoral thesis, Uppsala University, Atomic and molecular physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4290.
This thesis addresses the electronic structure of vanadium and copper oxides using soft X-ray absorption (SXA) spectroscopy and resonant inelastic X-ray scattering (RIXS) at high brightness synchrotron radiation sources. In RIXS incident photons, tuned to the energy of specific absorption resonances, are inelastically scattered leaving behind a low energy valence excitation in the system studied. Effects of electron localization are reflected by the occurrence of low-energy excitations in form of dd- and charge-transfer excitations that are modelled by cluster calculations. Band-like states are dominating when the intermediate core excited state is delocalized.
RIXS at V 2p and O 1s resonances has been used to study the electronic structure of the monovalent vanadium oxides VO2 and V2O3, and of the mixed valence compounds, NaV2O5 and V6O13. For NaV2O5 and V6O13 significant contributions from localized low-energy excitations reflect the partly localized character of their valence band electronic structure, whereas VO2 and V2O3 appear mostly as band-like. Effects of carrier doping are addressed for the case of Mo doping into VO2 and reveal a quasi-rigid band behavior. In the cases of VO2 and V6O13 the temperature dependent metal-insulator transition could be monitored by following the spectral evolution of bands originating from V 3d and V 3d - O2p hybridized states. For Na2V3O7 nanotubes it was possible to selectively probe states from the apical and the basal oxygen sites of VO5 pyramids that constitute these nanotubes. Furthermore, the RIXS technique has been demonstrated to be highly valuable in characterizing the charge transfer processes that accompany lithium insertion into vanadium oxide battery cathodes. Finally, for insulating cuprates RIXS at O 1s, Cu 3p and Cu 3s resonances has been recorded at high-resolution for the detailed investigation of crystal field excitations.
Feng, Jiatai. "Low-energy excitations in some complex oxides by resonant inelastic X-ray scattering : RMnO3 (R = Tb, Dy) and Lu2V2O7". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066414.
The intriguing physical properties presented in some complex oxides of transition metals draw attention not only in fundamental research but also in applications, for instance, superconductivity, colossal magnetoresistance, multiferroicity. The strong electronic correlation is at the origin of these behaviours. The thesis is a contribution to both the experimental effort to determine the electronic structure of strongly correlated systems and the critical assesment of the theoretical models describing them. Experimentally, the work of is devoted to the investigations of the low-energy excitations (d-d excitations, charge transfer, …) of the ground state by resonant inelastic x-ray scattering. The experiments have been performed on the SEXTANTS beamline of SOLEIL synchrotron (France) using the high resolving power AERHA spectrometer. The analysis of the data has been focused on the determination of the the crystal field of the transition metal involved using the crystal field multiplets theory.Two systems have been investigated: the multiferroics RMnO3 (R = Tb, Dy) and the ferromagnetic Mott insulator Lu2V2O7
Söderström, Johan. "Soft X-ray Scattering Dynamics Close to Core Ionization Thresholds in Atoms and Molecules". Doctoral thesis, Uppsala University, Department of Physics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7832.
In this Thesis studies of highly excited states in gas-phase atoms and molecules (He, Ne, N2, O2, N2O and CO2) using a variety of synchrotron-radiation based techniques are presented. The three techniques used most frequently are X-ray-emission-threshold-electron coincidence (XETECO), X-ray emission spectroscopy (XES) and X-ray photoelectron spectroscopy (XPS) and they are all given a brief introduction.
The fluorescence yield (FY) from doubly excited states in helium near the N=2 threshold(s) has been investigated in weak static external magnetic and electric fields, but also in a field free environment. The FY spectra in weak static magnetic fields show the importance of including the diamagnetic interaction in the theoretical models. The presence of weak static electric fields shows that even weak fields (as low as 44 V/cm) has a great impact on the observed FY spectra. Resonant XES spectra from some of the first doubly excited states in helium has been recorded in a field free environment, and compared to theory.
The XETECO technique is presented and the first XETECO results from Ne, N2, O2, CO2 and N2O are shown, together with interpretations of possible threshold dynamics. I show that XETECO can be interpreted as threshold photoelectron spectra free from post collision interaction, and can hence be compared to above threshold XPS measurements. The observed below-threshold structures in the XETECO spectra are discussed and given a tentative explanation. The results from the analysis of the N2O XETECO spectrum lead to further investigations using XPS. Results showing the vibrational parameters and vibrationally resolved cross-sections and asymmetry parameters for N2O are presented together with theoretical predictions.
Marra, Pasquale [Verfasser], den Brink Jeroen [Akademischer Betreuer] van i Berndt [Akademischer Betreuer] Büchner. "Theoretical approach to Direct Resonant Inelastic X-Ray Scattering on Magnets and Superconductors / Pasquale Marra. Betreuer: Jeroen van den Brink. Gutachter: Berndt Büchner". Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://d-nb.info/1078839913/34.
Agåker, Marcus. "Double Excitations in Helium Atoms and Lithium Compounds". Doctoral thesis, Uppsala University, Atomic and molecular physics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6889.
This thesis addresses the investigation of doubly excited 2l´nl states in helium atoms and double core excitations in solid lithium compounds.
Measurements on He are made in field free environments and under the influence of electric and magnetic fields, using synchrotron based inelastic photon scattering. Cross sections for scattering to singly excited final states are directly determined and compared to theoretical results and are found to be in excellent agreement. Radiative and spin-orbit effects are quantified and are shown to play an important role in the overall characterization of highly excited He states below the N =2 threshold. A dramatic electric field dependence is also observed in the flourecence yield already for relatively weak fields. This signal increase, induced by electric as well as magnetic fields, is interpreted in terms of mixing with states of higher fluorescence branching ratios.
Double core excitations at the lithium site in solid lithium compounds are investigated using resonant inelastic x-ray scattering (RIXS). The lithium halides LiF, LiCl, LiBr and LiI are studied as well as the molecular compounds Li2O, Li2CO3 and LiBF4. States with one, as well as both, of the excited electrons localized at the site of the bare lithium nucleus are identified, and transitions which involve additional band excitations are observed. A strong influence of the chemical surrounding is found, and it is discussed in terms of the ionic character of the chemical bond.
Augustsson, Andreas. "Soft X-ray Emission Spectroscopy of Liquids and Lithium Battery Materials". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4526.
Collart, Emilie. "Excitations électroniques dans les matériaux fortement corrélés : l' apport de la diffusion inélestique résonante des rayons X". Paris 6, 2005. https://tel.archives-ouvertes.fr/tel-00113361.
Hahn, Anselm Wolfgang [Verfasser], Serena [Gutachter] DeBeer i Nils [Gutachter] Metzler-Nolte. "Development and application of resonant inelastic x-ray scattering spectroscopy in inorganic chemistry / Anselm Wolfgang Hahn ; Gutachter: Serena DeBeer, Nils Metzler-Nolte ; Fakultät für Chemie und Biochemie". Bochum : Ruhr-Universität Bochum, 2018. http://d-nb.info/1165304635/34.
Vorwerk, Christian Wolfgang. "Theoretical Spectroscopy of Ga2O3". Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22113.
To develop new semiconductor devices and improve the performance of existing ones, the exploration and understanding of novel materials is required. With an ultra-wide band gap of around 4.8 eV, Ga2O3 is a promising candidate for applications in UV-optoelectronics and power electronics. These applications have led to an increasing interest in its fundamental electronic and optical properties. In this thesis, we present a comprehensive first-principles study of the electronic excitations of Ga2O3 to contribute to the understanding of these fundamental properties. The thesis consists of two parts: In the first part, we present an all-electron many-body perturbation theory (MBPT) approach for consistent calculations of neutral core and valence excitations. It enables accurate calculation of absorption and inelastic scattering spectra in the optical, UV, and x-ray region. While these spectroscopic techniques probe either the valence or core excitations, resonant inelastic x-ray scattering (RIXS) reveals the interplay between the two. We present a novel expression for the RIXS cross section within our all-electron many-body formalism that allows for a detailed analysis of this interplay. We demonstrate the capability of our implementation to compute, analyze, and interpret the different spectroscopic techniques with selected examples of prototypical insulators. In the second part, we apply our approach to study valence excitations, as well as excitations of various core states, i.e. the gallium 1s, gallium 2p, and oxygen 1s states in Ga2O3 . Comparing the core spectra of Ga2O3 polymorphs, we find distinct differences that originate from their local environments. We determine the composition of valence and core excitons, and analyze their signatures in the various absorption and scattering spectra. Finally, we demonstrate how RIXS can be employed to provide a different viewpoint on the core and valence excitations and unravel the interplay between them.
Sugimoto, Koudai. "Theoretical Study of Electron Dynamics in Multi-Orbital Antiferromagnetic Metals". 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199089.
Rossi, Matteo. "La diffusion inélastique résonante de rayons X sur systèmes corrélés induit par l'interaction spin-orbite : applications scientifiques et développements instrumentaux". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY089/document.
Iridium oxides (iridates) have raised notable attention in the last decade due to the identification of a Mott insulating state realized by the joint action of crystal field, electron correlation, and spin-orbit coupling. Such state has been intensively investigated and novel quantum phases and excitations have been theoretically predicted and experimentally found. Undoubtedly, one of the most employed techniques to elucidate the low-energy physics of iridates is resonant inelastic X-ray scattering (RIXS). At the iridium L3 edge, it benefits from a particularly good energy resolution, which matches the energy scales of the relevant excitations, and from a favorable inelastic cross-section. The aim of the present thesis is twofold: conceive challenging instrumental upgrades that contribute to the advancement of the technique itself, and apply RIXS to inspect the magnetic and electronic properties of selected iridates.The main instrumental development concerns the design of a new RIXS spectrometer with polarization resolution. Polarization analysis of the scattered X-rays provides useful information about the symmetry and thus the nature of an excitation. However, it is rather unexploited because of severe technical challenges when energy resolution and efficiency must be preserved. The designed RIXS spectrometer with polarization analysis capabilities is still under construction, however the optical scheme has been validated by preliminary tests. Full polarization analysis is expected without degradation of energy resolution or efficiency with respect to current state-of-the-art RIXS spectrometers. Additional technical developments include sample-environment equipment to perform RIXS experiments in low-temperature and high-pressure conditions. The equipment has been successfully utilized to investigate the magnetic dynamics of the bilayer-perovskite Sr3Ir2O7 below its Néel temperature and up to 12 GPa. Our measurements provide additional observations that may sharpen the challenge to theoretical understanding of the magnetic dynamics of this material. Moreover, we demonstrate for the first time that RIXS experiments of the magnetic dynamics can be extended to unexplored thermodynamic conditions.Besides instrumental advances, additional experimental work has been carried out in order to study the magnetic and electronic excitations of the post-perovskite CaIrO3. Owing to its peculiar crystal structure, featuring both edge- and corner-sharing octahedra, the magnetic interactions of CaIrO3 are very different along orthogonal directions. In particular, the inhibition of the Heisenberg coupling along the edge-sharing direction induces one-dimensional magnetic behavior with characteristic fractional spinon-like excitations, which have been detected by RIXS. Electronic excitations are also found to have particular properties. Finally, I have focused on the electronic structure of Rb2[IrF6], which was theoretically predicted to realize a Mott insulating state similar to the one of iridium oxides. RIXS measurements helped to elucidate the electronic properties of this compound. The robustness of the electronic state has been tested against substitutions of the alkali metal and halogen, and application of physical pressure.The present work extends the potential of the RIXS technique to domains previously unexplored, i.e. polarization analysis of the scattered X-rays and high-pressure low-temperature experiments. I hope that the instrumental upgrades and applications of RIXS discussed in this thesis will further promote the technique as a powerful and reliable tool to characterize elementary excitations in correlated-electron systems
Fahleson, Tobias. "Derivation and application of response functions for nonlinear absorption and dichroisms". Doctoral thesis, KTH, Teoretisk kemi och biologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-218662.
QC 20171129
Desjacques, Charlotte. "Apports des méthodes photon-in/photon-out à la compréhension des systèmes catalytiques complexes". Electronic Thesis or Diss., Université de Lille (2018-2021), 2018. http://www.theses.fr/2018LILUR013.
The aim of this PhD dissertation is to apply resonant inelastic X-Ray scattering (RIXS 1s2p) and high energy resolution partial fluorescence detection X-ray absorption spectroscopy (HERPFD-XAS) to the study in situ sulfurization of HDS catalysts. Indeed, only a detailed understanding of the structure and nature of the active phase of the catalysts at the molecular level makes it possible to improve their catalytic performance. After presenting a state of the art on the characterization of the active phase of hydrotreating catalysts, we have shown the potential of these spectroscopic methods through the study of cobalt-based reference compounds where cobalt is present in different symmetries with different oxidation states. These results reveal that these spectroscopic techniques are sensitive to the local coordination of cobalt, as well as to its electronic structure. Two samples were studied for in situ sulfurization: cobalt supported on alumina and cobalt-molybdenum supported on alumina. The HERPFD-XAS spectroscopy results at cobalt K-edge show CoS2 formation before the CoMoS and Co9S8 phases for both samples, as well as the constant contribution of CoAl2O4 (phase that does not undergo sulfurization). Analysis by 1s2p RIXS spectroscopy revealed that the cobalt, present in the active phase of the both catalyst, has a metallic character, which allowed to interpret in a finer way data published in the literature
Natori, Willian Massashi Hisano. "j = 3/2 Quantum spin-orbital liquids". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-25092018-161836/.
Líquidos de spin quânticos (QSLs) são sistemas fortemente correlacionados que apresentam fenômenos fascinantes como emaranhamento de longo alcance e excitações fracionárias. A pesquisa a respeito destes estados seguiu tendências geradas pela síntese de novos compostos e construção de novas técnicas teóricas desde seu princípio. Coerentemente com essa história, uma variedade de novos resultados a respeito de líquidos de spin foram estabelecidos na última década graças a estudos feitos sobre o modelo integrável de Kitaev na rede colmeia. Este modelo de spins j = 1/2 apresenta interações de troca anisotrópicas e direcionalmente dependentes que são essenciais para estabilizar um estado fundamental do tipo QSL com férmions de Majorana e campo de gauge Z2 emergente. Ainda mais interessante, este modelo é relevante para se entender o magnetismo de uma certa classe de isolantes de Mott baseados em metais de transição na configuração 4/5d5 em redes específicas, degenerescência orbital t2g e acoplamento spin-órbita forte (SOC). Esse mecanismo que define os chamados materiais do tipo Kitaev podem ser aplicados a compostos baseados em metais de transição em configurações eletrônicas diferentes. Nesta tese, eu investigo modelos mínimos para dois tipos de isolantes de Mott do tipo 4/5d1: os que se apresentam na estrutura perovskita dupla ordenada (ODP) e os isostruturais aos materiais do tipo Kitaev. Seus modelos efetivos genericamente apresentam interações multipolares anisotrópicas e direcionalmente dependentes de um momento angular efetivo j = 3/2. Estes graus de liberdade são convenientemente escritos em termos de operadores de pseudospin s e pseudo-orbital τ semelhantes a operadores de spin e orbital de modelos do tipo Kugel-Khomskii com orbitais duplamente degenerados. A despeito da anisotropia, esses dois modelos realísticos apresentam simetrias globais contínuas no limite de acoplamento de Hund nulo que incrementam flutuações quânticas e possivelmente estabilizam uma fase do tipo QSL. A teoria de campo médio com partons foi usada para propor QSLs fermiônicos que serão chamados de líquidos spin-orbitais quânticos (QSOLs) devido à dependência deles com s e τ. Em ODPs, eu estudei um líquido de spin quiral com excitações do tipo férmion de Majorana e um espectro sem gap caracterizado por linhas nodais ao longo das arestas da zona de Brillouin. Essas linhas nodais são defeitos topológicos de uma conexão de Berry não-abeliana e o sistema apresenta estados de superfície dispersivos. Várias respostas experimentais foram calculadas para o QSOL quiral dentro da aproximação de campo médio e comparadas com os dados experimentais disponíveis para o candidato a líquido de spin Ba2YMoO6. Além disso, baseado em uma análise de simetria, discuto os operadores envolvidos nas amplitudes de espalhamento de raios-x ressonante para isolantes de Mott na configuração 4/5d1 e mostro que seções de choque de RIXS permitem estudar seletivamente os graus de liberdade de pseudospins e pseudo-orbitais. Para o caso particular do líquido spin-orbital quiral, essas seções de choque nos fornecem informações sobre o espectro de diferentes sabores de férmions de Majorana. Esse modelo possui uma simetria SU(4) emergente que é tornada explícita através de uma transformações de Klein nos graus de liberdade de pseudospin. Sabe-se que este modelo estabiliza um QSOL na rede colmeia, o que instigou uma investigação de QSOLs na generalização desta rede em três dimensões. A teoria de campo médio com partons foi usada novamente para propor estes líquidos quânticos, e o método de Monte Carlo Variacional (VMC) foi usado para calcular as energias das funções de onda projetadas. Os resultados numéricos mostraram que o QSOL de menor energia corresponde a um estado de fluxo-zero com superfície de Fermi envolvendo partons fermiônicos de quatro cores. Cálculos adicionais com VMC também demonstraram que este estado é estável à formação de ordem de plaquetas (tetramerização). A energia deste QSOL é altamente competitiva mesmo quando perturbações induzidas pelo acoplamento de Hund são incluídas, o que é mostrado através da comparação com estados ordenados simples. Extensões e perspectivas para trabalhos futuros são discutidas no final desta tese.
Wu, Cheng-Yau, i 吳承曜. "Resonant inelastic X-ray scattering on High Tc Superconductor". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/y7emfj.
國立交通大學
物理研究所
106
In spite of intensive studies by experimentalist and theorist on high temperature superconducting cuprates (HTSC) over the past decades by experimentalists and theorists, a full understanding of HTSC theories still not available. The information of unoccupied and occupied electronic structures can be inferred from X-ray absorption and photoelectron spectroscopy respectively. However, there remains debates on the details of relevant energetic scales for describe the cuprate physics. Resonant inelastic X-ray scattering is a technique that involves absorption and emission process, and under resonant condition, specific intermediate states can be accessed, which provides electronic structure information unavailable from aforementioned methods. In 1993, Tanaka and Kotani [1] pointed out that in La2CuO4 and CuO2 the direct inter-d-orbital transitions are not allowed because of the diploe transition rule until in 2005that G. Ghiringhelli et al. successfully measured the Cu-L3 edge spectrum of La2-xSrxCuO4 and found its excitation behavior at different doping levels with resonance inelastic X-ray scattering(RIXS) technique. However, due to strong spectral weight transfer from higher energy loss and the leak of superior energy resolution, they could not better resolve d-d excitations.[2] In this thesis, Resonance Inelastic X-ray Scattering (RIXS) experiments were carried out using the beam line 4.0.3 (MERLIN) at Advanced Light Source, Lawrence Berkeley National Laboratory, to investigate the low energy excitations of high temperature superconductors thin films. The thin films were fabricated by Pulse Laser Deposition (PLD) system. The Sr concentrations of La2-xSrxCuO4 were controlled by the targets made by solid state reaction method. The oxygen doping of YBa2Cu3O7-δ were controlled by post-annealing in a heat treatment system. By using the superior VUV (Vacuum ultraviolet) spectrometer at MERLIN beamline, at Cu M-edge, we have observed the low energy excitations and explored the mechanism in details. Incident photon energy dependent spectra from samples with different hole doping levels have also been recorded. The results show that the low excitations are differences in different doping levels.
Luo, Jin. "Scattering operator for elastic and inelastic resonant x-ray scattering". Thesis, 1994. http://hdl.handle.net/1911/16754.
Lin, Guan-Yuan, i 林冠緣. "Electronic excitations of Fe3O4 revealed by resonant inelastic X-ray scattering". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/71754421445078608596.
國立交通大學
加速器光源科技與應用碩士學位學程
100
The electronic structure of strongly correlated electronic systems is an important subject in condensed matter physics. The properties of solids are related to the electronic states of outer electrons, the valence electron states. Resonant inelastic X-ray scattering (RIXS) is a powerful tool to study the electron excitations in solids. From the excitation and de-excitation processes, the electronic structure can be further revealed. We here investigated the magnetic properties of magnetite (Fe3O4) by measuring and calculating the 1s2p RIXS spectra. We also recorded the signal of magnetic circular dichroism by measuring the 1s2p RIXS. The mixed valence and multisite of [Fe3]tetra[Fe2Fe3]octaO4 are recognized in the RIXS-MCD spectra. The RIXS-MCD spectra obtained with opposite helicities of circularly polarized incident x-rays are consistent with the simulations by the charge transfer multiplet model.
Ellis, David. "Electronic Excitations in Lanthanum Cuprates Measured by Resonant Inelastic X-ray Scattering". Thesis, 2010. http://hdl.handle.net/1807/24344.
Lai, Chia-Hung, i 賴嘉宏. "Measurements of Resonant Inelastic Soft X-ray Scattering on NiO and CuO". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/17898334428590179980.
國立清華大學
物理系
102
Resonant inelastic X-ray scattering (RIXS) is a powerful technique for studying electronic structure. In the soft X-ray regime, RIXS provides essential information about local and collective excitations which can't be obtained from other X-ray spectroscopic methods, such as X-ray absorption spectroscopy (XAS) and photoemission spectroscopy. However, a RIXS measurment requires high photon flux. In order to increase the efficiency of RIXS measurement, we developed a highly efficient beamline and spectrometer of inelastic soft X-ray scattering at high resolution. The design and construction of the beamline and spectrometer was based on the energy compensation principle of grating dispersion. We used two bendable gratings to achieve a good energy resolution by eliminating the defocus and comma aberrations. The total resolving power for incident photon energy covering from the Fe L3-edge to the Cu L3-edge was between 7500 and 10,000. The design of this monochromator-spectrometer system also greatly enhances the efficiency of measurement of inelastic soft X-rays scattering. In this dissertation, we present commissioning results of this new RIXS beamline and its capability of measuring momentum-resolved RIXS of NiO and CuO.
Huang, Hsiao-Yu, i 黃筱妤. "Magnetic Excitations of Correlated Electrons Probed by Resonant Inelastic X-ray Scattering". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/53670271020918418532.
國立清華大學
先進光源科技學位學程
104
Resonant inelastic X-ray scattering (RIXS), a photon-in and photon-out spectroscopy method, has been used to probe two representative compounds, the optimally doped superconducting cuprate Bi1.5Pb0.6Sr1.54CaCu2O8+δ (Bi2212) and the first magnetic material found by mankind - magnetite Fe3O4. Investigation of collective magnetic excitations in cuprate superconductors is an important subject in searching the paring mechanism of high Tc superconductivity. In comparison with inelastic neutron scattering, RIXS reveals the existence of high-energy magnetic excitations in doped superconducting cuprates. However, the interpretation of such excitations remains in dispute. Here we show the dependence of Cu L3 RIXS on the energy and polarization of incident photons in optimally doped high-Tc cuprate superconductors Bi2212. Two distinct types of excitations, Raman-like and fluorescence-like, were observed by using π- and σ-polarized incident X-rays, respectively. Combined with calculations of exact diagonalization, we demonstrate the nature of collective damped magnetic excitations measured with -polarized RIXS. Fe3O4 has been studied for decades to understand the Verwey transition. The mech- anism of the simultaneous drop of electric conductivity and a complex structural phase transition has been one of the most extensively studied problems in condensed matter physics. We used RIXS to unravel the local electronic structures of different Fe sites in Fe3O4. Local spin excitations are observed on the octahedral Fe3+ sites with an effective exchange field of 90 meV. Markedly we found a broad excitation feature with an energyof 200 meV for Fe2+. With the help of multiplet calculations, a tetragonal distortion of strength t2g =
Huang, Hsiao-Yu, i 黃筱妤. "Electronic Excitations of NiO and CoO Revealed by Resonant Inelastic Soft X-ray Scattering". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/06012703837886827620.
國立清華大學
物理學系
97
The electronic structure of strongly correlated electronic systems is an important issue in condensed matter physics, since the discovery of various interesting phenomena arising from strong correlations, such as superconductivity, colossal magnetoresistance, ...etc. Resonant inelastic X-ray scattering (RIXS) in the soft X-ray range is a powerful probe to investigate electronic excitations in solids. By measuring the excitation energies and the dependence of momentum transfer, the electronic structure can be further revealed. In this thesis, we performed measurements of resonant inelastic soft X-ray scattering on NiO and CoO, by using a newly designed beamline based on an energy compensation principle. Two optically identical, actively bendable gratings were used as the monochromator and spectrometer. The RIXS spectra at L-edge with a combined energy resolution at 240 meV were obtained. We assigned different energy-loss features of electronic excitations from RIXS spectra to the dd excitations and charge-transfer excitations. The dd excitations are interpreted by the crystal field theory, and the crystal field strength (10Dq) is obtained. The RIXS spectra obtained with different incident photon energies are consistent well with the simulations by the single impurity Anderson model.
Hu, Chia-Wei, i 胡家瑋. "Resonant inelastic X-ray scattering study of quasi-one-dimensional cuprate LiCu2O2 at Cu K-edge". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/25514738098898228822.
Sternemann, Henning [Verfasser]. "A non-resonant inelastic x-ray scattering study on silicon oxides and clathrates / vorgelegt von Henning Sternemann". 2008. http://d-nb.info/997720158/34.
Anquillare, Emma L. B. "X-ray spectroscopy of electronic band structure in vanadium oxide nanoparticles". Thesis, 2021. https://hdl.handle.net/2144/43086.
Xu, Lei. "Ab initio modeling of the electronic structure of d-metal systems and of resonant inelastic X-ray scattering responses". 2019. https://tud.qucosa.de/id/qucosa%3A35076.
Wang, Shun-Hung, i 王舜鴻. "Spectroscopy studies of quantum matter: (Ⅰ)Ultrafast dynamics of FeSe and YBaCuFeO5 (Ⅱ)Resonant inelastic X-ray scattering on YBa2Cu3O7-δ". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/29590863785879539808.
國立交通大學
物理研究所
103
In this thesis, we studied the low energy excitation of superconductor YBa2Cu3O7-δ films by using resonant inelastic X-ray scattering. All the YBa2Cu3O7-δ thin films were grown by the PLD and the oxygen contents of YBa2Cu3O7-δ films were control with the annealing system. The results of energy dependence of RIXS show that the excitations of d electrons are different with various hole dopings. Besides, in this thesis we measured FeSe single crystals by pump-probe system. At the structure transformation temperature 90 K, the structure with two-fold symmetry transforms into four-fold symmetry. However we would like to understand what mechanism to change the symmetry. Therefore, the measurements in this study include two parts: the dependence of temperature and polarization angle of pump probe beams. The results indicate the mechanism of electron nematic order persisted up to 150 K. Finally, we measured YBaCuFeO5 single crystals by pump-probe system. Besides, a M-T curve indicates that the AFM transformations are emerged at low temperature 175 K and high temperature 475 K, which shows a commensurate to incommensurate magnetic structure phase transition at TN1~175 K. Therefore, we measured the transient reflectivity changes at various temperatures to study the relaxation behavior of photoexcited carriers. We observed that the spin-lattice thermalization time and spin reordering time change obviously at the transition between commensurate phase and incommensurate phase. In addition, the coupling strength between lattice and spin gradually increases with decreasing temperatures.
Kusch, Maximilian. "Magnetic excitations and ordering phenomena in iridium compounds studied by synchrotron techniques". 2020. https://tud.qucosa.de/id/qucosa%3A74796.
Robledo, José Ignacio. "Avances en espectroscopía por dispersión inelástica resonante de rayos X en baja y alta resolución". Doctoral thesis, 2019. http://hdl.handle.net/11086/11285.
La presente tesis doctoral está centrada en el uso de la Dispersión Inelástica Resonante de Rayos X (RIXS) para la determinación del entorno químico de un átomo emisor a partir de espectros colectados mediante sistemas dispersivos en energía, los cuales pueden obtenerse en laboratorios de rayos X convencionales o en facilidades sincrotrón. En la primera parte de esta tesis se describe la técnica EDIXS (Energy Dispersive Inelastic X-Ray Scattering ) que desarrollamos en base al uso de métodos multivariados para extraer información de espectros RIXS, colectados por un sistema dispersivo en energía y con un haz incidente monocromático. En la segunda parte se describe el diseño, construcción y funcionamiento de un nuevo espectrómetro. Este sistema está basado en un cristal analizador de forma cónica discreta, que selecciona los fotones provenientes de la muestra emisora y los difracta hacia distintas posiciones de la superficie de un detector sensible a la posición.
This thesis is focused in the use of Resonant Inelastic X-Ray Scattering (RIXS) in energy dispersive mode for chemical environment characterization of the emitting atoms. These spectra may be easily obtained in synchrotron radiation facilities and also in conventional x-ray laboratories. The thesis is divided in two parts. The first one describes our technique, called Energy Dispersive Inelastic X-Ray Scattering (EDIXS), which is based in the use of multivariate statistical analyses for extracting information from RIXS spectra measured with energy dispersive systems, and a monochromatic beam. The second part is dedicated to the design, construction and fabrication of a new spectrometer, consisting on a crystal analyzer with a "Discrete Conical" shape, that selects photons emitted from the sample and diffracts them towards the surface of a position sensitive detector.
Enkisch, Hartmut [Verfasser]. "Bloch k-selective resonant inelastic scattering of hard X-rays from valence electrons of 3d-metals / vorgelegt von Hartmut Enkisch". 2001. http://d-nb.info/964267276/34.