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http://dx.doi.org/10.18419/opus-10995
Autor(en): | Toloui-Mantadakis, Daniil |
Titel: | Realistic calculations for correlated materials |
Erscheinungsdatum: | 2019 |
Dokumentart: | Dissertation |
Seiten: | x, 128 |
URI: | http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-ds-110125 http://elib.uni-stuttgart.de/handle/11682/11012 http://dx.doi.org/10.18419/opus-10995 |
Zusammenfassung: | Strongly correlated fermionic systems nowadays stand in the forefront of condensed matter physics. A plethora of phenomena, ranging from unconventional superconductivity, gigantic and colossal magneto-resistance and metal-to-insulator transitions, are attributed to the effects of electron correlation. Given the spectacular progress on the experimental side, today - more than ever - the understanding of the underlying microscopic mechanisms, and the explanation or even prediction of experimental observations becomes a necessity. The advancements of theoretical and computational methodologies together with a concurrent increase of computational power, allows for both the ab initio study of realistic materials and the investigation of low-energy effective Hamiltonians inspired and designed to resemble whole classes of compounds. This work is conceptually divided into two major parts. In Chapter 3 and Chapter 4, we present our results, obtained by the state-of-the-art merger of density functional and dynamical mean-field theory, for two realistic systems: the layered LaNiO2/LaGaO3 superstructure, where we focus on the orbital resolved single-particle spectral functions and study the effect of electron and hole doping; and the ruthenate system Ca2RuO4, for which we provide a clear understanding and theoretical support of the experimentally observed semi-metallic state under the application of DC current. The second conceptual part of this work deals with the study of low-energy effective Hamiltonians. In Chapter 4, we investigate a generic t2g model Hamiltonian in the presence of non-spherical crystal-field potentials and/or spin-orbit coupling in order to shed more light on the distinct features that arise on the single-particle level and, most importantly, on the two-particle observables, such as the uniform and static magnetic susceptibilities. In Chapter 5, we investigate the multi-orbital extension of the periodic Anderson model, as inspired by the family of cerium-based heavy-fermion compounds, with a clear focus on the evolution of the dynamic behavior of the systems' moments. |
Enthalten in den Sammlungen: | 08 Fakultät Mathematik und Physik |
Dateien zu dieser Ressource:
Datei | Beschreibung | Größe | Format | |
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dissertation_v2.pdf | 2,88 MB | Adobe PDF | Öffnen/Anzeigen |
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