Dynamical Mean-Field Theory for Strongly Correlated Materials PDF Download
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Author: Volodymyr Turkowski
Publisher: Springer Nature
ISBN: 3030649040
Category : Technology & Engineering
Languages : en
Pages : 393
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Book Description
This is the first book that provides a detailed summary of one of the most successful new condensed matter theories - dynamical mean-field theory (DMFT) - in both static and dynamical cases of systems of different sizes. DMFT is one of the most successful approaches to describe the physical properties of systems with strong electron-electron correlations such as bulk materials, multi-layers, surfaces, 2D materials and nanostructures in both metallic and insulating phases. Strongly correlated materials usually include partially-filled localized d- or f-orbitals, and DMFT takes into account crucial for these systems time-resolved interaction between electrons when they “meet” on one atom and occupy one of these orbitals. The First Part of the book covers the general formalism of DMFT as a many-body theory, followed by generalizations of the approach on the cases of finite systems and out-of-equilibrium regime. In the last Chapter of the First Part we discuss generalizations of the approach on the case when the non-local interactions are taken into account. The Second Part of the book covers methodologies of merging DMFT with ab initio static Density Functional Theory (DFT) and Time-Dependent DFT (TDDFT) approaches. Such combined DFT+DMFT and DMFT+TDDFT computational techniques allow one to include the effects of strong electron-electron correlations at the accurate ab initio level. These tools can be applied to complex multi-atom multi-orbital systems currently not accessible to DMFT. The book helps broad audiences of students and researchers from the theoretical and computational communities of condensed matter physics, material science, and chemistry to become familiar with this state-of-art approach and to use it for reaching a deeper understanding of the properties of strongly correlated systems and for synthesis of new technologically-important materials.
Author: Volodymyr Turkowski
Publisher: Springer Nature
ISBN: 3030649040
Category : Technology & Engineering
Languages : en
Pages : 393
Get Book Here
Book Description
This is the first book that provides a detailed summary of one of the most successful new condensed matter theories - dynamical mean-field theory (DMFT) - in both static and dynamical cases of systems of different sizes. DMFT is one of the most successful approaches to describe the physical properties of systems with strong electron-electron correlations such as bulk materials, multi-layers, surfaces, 2D materials and nanostructures in both metallic and insulating phases. Strongly correlated materials usually include partially-filled localized d- or f-orbitals, and DMFT takes into account crucial for these systems time-resolved interaction between electrons when they “meet” on one atom and occupy one of these orbitals. The First Part of the book covers the general formalism of DMFT as a many-body theory, followed by generalizations of the approach on the cases of finite systems and out-of-equilibrium regime. In the last Chapter of the First Part we discuss generalizations of the approach on the case when the non-local interactions are taken into account. The Second Part of the book covers methodologies of merging DMFT with ab initio static Density Functional Theory (DFT) and Time-Dependent DFT (TDDFT) approaches. Such combined DFT+DMFT and DMFT+TDDFT computational techniques allow one to include the effects of strong electron-electron correlations at the accurate ab initio level. These tools can be applied to complex multi-atom multi-orbital systems currently not accessible to DMFT. The book helps broad audiences of students and researchers from the theoretical and computational communities of condensed matter physics, material science, and chemistry to become familiar with this state-of-art approach and to use it for reaching a deeper understanding of the properties of strongly correlated systems and for synthesis of new technologically-important materials.
Author: Steffen Backes
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Alamgir Kabir
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659900907
Category :
Languages : en
Pages : 216
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Book Description
In this book, Density Functional Theory (DFT) and Dynamical Mean-Field Theory (DMFT) approaches are applied to study the magnetic properties of transition metal nanosystems of different sizes and compositions. In particular, in order to take into account dynamical electron correlation effects (time-resolved local charge interactions), we have adopted the DFT+DMFT formalism and made it suitable for application to nanostructures. Preliminary application of this DFT+DMFT approach, using available codes, to study the magnetic properties of small (2 to 5-atom) Fe and FePt clusters provide meaningful results: dynamical effects lead to a reduction of the cluster magnetic moment as compared to that obtained from DFT or DFT+U (U being the Coulomb repulsion parameter). We have subsequently developed our own nanoDFT+DMFT code and applied it to examine the magnetization of iron particles containing10-147 atoms. Our results for the cluster magnetic moments are in a good agreement with experimental data. In particular, we are able to reproduce the oscillations in magnetic moment with size as observed in the experiments.
Author: Johannes Ferber
Publisher:
ISBN:
Category :
Languages : en
Pages : 125
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Book Description
Author: Alamgir Kabir
Publisher:
ISBN:
Category :
Languages : en
Pages : 189
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Book Description
In this thesis, Density Functional Theory (DFT) and Dynamical Mean-Field Theory (DMFT) approaches are applied to study the magnetic properties of transition metal nanosystems of different sizes and compositions. In particular, in order to take into account dynamical electron correlation effects (time-resolved local charge interactions), we have adopted the DFT+DMFT formalism and made it suitable for application to nanostructures. Preliminary application of this DFT+DMFT approach, using available codes, to study the magnetic properties of small (2 to 5-atom) Fe and FePt clusters provide meaningful results: dynamical effects lead to a reduction of the cluster magnetic moment as compared to that obtained from DFT or DFT+U (U being the Coulomb repulsion parameter). We have subsequently developed our own nanoDFT+DMFT code and applied it to examine the magnetization of iron particles containing10-147 atoms. Our results for the cluster magnetic moments are in a good agreement with experimental data. In particular, we are able to reproduce the oscillations in magnetic moment with size as observed in the experiments.
Author: John M. Wills
Publisher: Springer
ISBN: 9783642151453
Category : Science
Languages : en
Pages : 200
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Book Description
This is a book describing electronic structure theory and application within the framework of a methodology implemented in the computer code RSPt. In 1986, when the code that was to become RSPt was developed enough to be useful, it was one of the ?rst full-potential, all-electron, relativistic implem- tations of DFT (density functional theory). While RSPt was documented p- asitically in many publications describing the results of its application, it was many years before a publication explicitly describing aspects of the method appeared. In the meantime, several excellent all-electron, full-potential me- ods had been developed, published, and become available. So why a book about RSPt now? The code that became RSPt was initially developed as a personal research tool, rather than a collaborative e?ort or as a product. As such it required some knowledge of its inner workings to use, and as it was meant to be m- imally ?exible, the code required experience to be used e?ectively. These - tributes inhibited, but did not prevent, the spread of RSPt as a research tool. While applicable across the periodic table, the method is particularly useful in describing a wide range of materials, including heavier elements and c- pounds, and its ?exibility provides targeted accuracy and a convenient and accurate framework for implementing and assessing the e?ect of new models.
Author: Jean-Marc Robin
Publisher: Lulu.com
ISBN: 1446638847
Category : Science
Languages : en
Pages : 166
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Book Description
This book is a short introduction to the Dynamical Mean-Field Theory for strongly correlated electrons. Its purpose is to focus on various local decoupling schemes in order to derive a self-consistent approximation and to map the lattice problem onto an impurity problem. Hubbard, Holstein, and Falicov-Kimball models are mainly used to provide examples of calculation. Numerous basic c/c++ programs are given along the book to develop confidence in computing actual numerical results.
Author: Krzysztof Dymkowski
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Eberhard Engel
Publisher: Springer Science & Business Media
ISBN: 3642140904
Category : Science
Languages : en
Pages : 543
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Book Description
Density Functional Theory (DFT) has firmly established itself as the workhorse for atomic-level simulations of condensed phases, pure or composite materials and quantum chemical systems. This work offers a rigorous and detailed introduction to the foundations of this theory, up to and including such advanced topics as orbital-dependent functionals as well as both time-dependent and relativistic DFT. Given the many ramifications of contemporary DFT, the text concentrates on the self-contained presentation of the basics of the most widely used DFT variants: this implies a thorough discussion of the corresponding existence theorems and effective single particle equations, as well as of key approximations utilized in implementations. The formal results are complemented by selected quantitative results, which primarily aim at illustrating the strengths and weaknesses of particular approaches or functionals. The structure and content of this book allow a tutorial and modular self-study approach: the reader will find that all concepts of many-body theory which are indispensable for the discussion of DFT - such as the single-particle Green's function or response functions - are introduced step by step, along with the actual DFT material. The same applies to basic notions of solid state theory, such as the Fermi surface of inhomogeneous, interacting systems. In fact, even the language of second quantization is introduced systematically in an Appendix for readers without formal training in many-body theory.
Author: Anirban Bhattacharyya
Publisher:
ISBN:
Category : Density functionals
Languages : en
Pages :
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Book Description
Abstract: Density functional theory (DFT) is a tool of many-body physics whose popularity has grown over the years, primarily because it provides a useful balance between accuracy and computational cost, allowing large systems to be treated in a simple self-consistent manner. Effective field theory (EFT) is a framework which allows us to study the low-energy phenomena of a system in a systematic fashion. In this thesis, EFT methods are applied to DFT as part of a program to systematically go beyond mean-field approaches to medium and heavy nuclei. A system of fermions with short-range, natural interactions and an external confining potential (e.g., fermionic atoms in an optical trap) serves as a laboratory for studying DFT/EFT. An effective action formalism leads to a Kohn-Sham DFT by applying an inversion method order-by-order in the EFT expansion parameter. Results showing the convergence of Kohn-Sham calculations at zero temperature in the local density approximation (LDA) are compared to Thomas-Fermi calculations and to power-counting estimates. When conventional Kohn-Sham DFT for Coulomb systems is extended beyond the local density approximation, the kinetic energy density is sometimes included in energy functionals in addition to the fermion density. However, a local (semi-classical) expansion of the kinetic energy density is used to write the energy as a functional of the density alone, in contrast to the Skyrme approach. The difference is manifested in different single-particle equations, which in the Skyrme case include a spatially varying effective mass. The EFT framework for DFT is generalized to reconcile these approaches. An effective action approach is used to illustrate how the exact Green's function can be calculated in terms of the Kohn-Sham Green's function. An example based on Skyrme energy functionals shows that single-particle Kohn-Sham spectra can be improved by adding sources used to construct the energy functional. Finally, spin-orbit interactions are incorporated in the formalism leading to an energy functional having the same form as that of the Skyrme functional. Gradient expansions in terms of the local Fermi momentum are also worked out, which will be of use in the immediate future.
