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Calculation of electron structure in the framework of DTF in real space
Čertík, Ondřej ; Vackář, Jiří (advisor) ; Šipr, Ondřej (referee)
In the present work we study ab-initio electronic structure calculations in real space using density functional theory (DFT), finite elements and pseudopotentials. We summarize the theory and full ab-initio derivation of all equations in finite elements, density functional theory and pseudopotentials, then we explain how our program works and we show results for spherically symmetric potentials in relativistic and nonrelativistic DFT and for 2D and 3D Schrödinger equation for symmetric and non-symmetric potentials.
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Theory of spin-dependent transport in magnetic solids
Wagenknecht, David ; Turek, Ilja (advisor) ; Minár, Ján (referee) ; Šipr, Ondřej (referee)
of doctoral thesis Theory of spin-dependent transport in magnetic solids David Wagenknecht Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University 2019 Theoretical and ab initio description of realistic material behavior is complicated and combinations of various scattering mechanisms or temperature effects are often neglected, although experimental samples contain impurities and modern electronics work at finite temperatures. In order to remove these knowledge gaps, the alloy analogy model is worked out in this thesis and implemented within the fully relativistic tight- binding linear-muffin-tin orbital method with the coherent potential approximation. This first-principles framework is shown to be robust and computationally efficient and, consequently, employed to investigate bulk solids and their spintronic applications. Unified effect of phonons, magnons, and alloying gives agreement with literature for temperature-dependent electrical transport (longitudinal and anomalous Hall resistivities) and scattering mechanisms are explained from electronic structures. Moreover, novel data help to identify defects in real samples and experimentally hardly accessible quantities are presented, such as spin polarization of electrical current. Calculated results for both zero...
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Theory of spin-dependent transport in magnetic solids
Wagenknecht, David ; Turek, Ilja (advisor) ; Minár, Ján (referee) ; Šipr, Ondřej (referee)
of doctoral thesis Theory of spin-dependent transport in magnetic solids David Wagenknecht Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University 2019 Theoretical and ab initio description of realistic material behavior is complicated and combinations of various scattering mechanisms or temperature effects are often neglected, although experimental samples contain impurities and modern electronics work at finite temperatures. In order to remove these knowledge gaps, the alloy analogy model is worked out in this thesis and implemented within the fully relativistic tight- binding linear-muffin-tin orbital method with the coherent potential approximation. This first-principles framework is shown to be robust and computationally efficient and, consequently, employed to investigate bulk solids and their spintronic applications. Unified effect of phonons, magnons, and alloying gives agreement with literature for temperature-dependent electrical transport (longitudinal and anomalous Hall resistivities) and scattering mechanisms are explained from electronic structures. Moreover, novel data help to identify defects in real samples and experimentally hardly accessible quantities are presented, such as spin polarization of electrical current. Calculated results for both zero...
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Study of the effect of spin-orbit interaction in solids
Mrozek, Jan ; Carva, Karel (advisor) ; Šipr, Ondřej (referee)
One of the effects the spin orbit interaction leads to is the Anomalous Hall effect. In this thesis we describe the origins of the Anomalous Hall effect and its con- tribution to understanding the solid state physics. We introduce the formalism of linear response theory and other approximations needed to perform calcula- tions of the Anomalous Hall conductivity. We present two different models of the anomalous Hall conductivity - one based on the Kubo formalism and the other based on chemical potential difference. We then compare the models in a simple setting based on Strontium ruthenate. We show that in the case of Strontium ruthenate the models have very similar predictions. 1
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Calculation of electron structure in the framework of DTF in real space
Čertík, Ondřej ; Vackář, Jiří (advisor) ; Šipr, Ondřej (referee)
In the present work we study ab-initio electronic structure calculations in real space using density functional theory (DFT), finite elements and pseudopotentials. We summarize the theory and full ab-initio derivation of all equations in finite elements, density functional theory and pseudopotentials, then we explain how our program works and we show results for spherically symmetric potentials in relativistic and nonrelativistic DFT and for 2D and 3D Schrödinger equation for symmetric and non-symmetric potentials.
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