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In this thesis, magnetism and transport phenomena in spin-charge coupled systems on frustrated lattices are theoretically investigated, focusing on Ising-spin Kondo lattice models and using a combination of Monte Carlo simulation and other techniques such as variational calculations and perturbation theory. The emphasis of the study is on how the cooperation of spin-charge coupling and geometrical frustration affects the thermodynamic properties of the Kondo lattice models; it presents the emergence of various novel magnetic states, such as the partial disorder, loop-liquid, and spin-cluster states. The thesis also reveals that the magnetic and electronic states and transport properties of these models demonstrate peculiar features, such as Dirac half-metals, anomalous Hall insulators, and spin Hall effects. Study of novel magnetic states and exotic transport phenomena in Kondo lattice systems is a field experiencing rapid progress. The interplay of charge and spin degrees of freedom potentially gives rise to various novel phases and transport phenomena which are related to strongly correlated electrons, frustrated magnetism, and topological states of matter. The results presented in this thesis include numerical calculations that are free from approximations. Accordingly, they provide reliable reference values, both for studying magnetism and transports of related models and for experimentally exploring novel states of matter in metallic magnets.

Quantum mechanics. Quantumfield theory --- Electromagnetism. Ferromagnetism --- Thermal properties of solids --- Solid state physics --- supergeleiding --- vaste stof --- quantumfysica --- materie (fysica) --- magnetisme

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This volume presents an in-depth review of experimental and theoretical studies on the newly discovered Fe-based superconductors. Following the Introduction, which places iron-based superconductors in the context of other unconventional superconductors, the book is organized into three sections covering sample growth, experimental characterization, and theoretical understanding. To understand the complex structure-property relationships of these materials, results from a wide range of experimental techniques and theoretical approaches are described that probe the electronic and magnetic properties and offer insight into either itinerant or localized electronic states. The extensive reference lists provide a bridge to further reading. Iron-Based Superconductivity is essential reading for advanced undergraduate and graduate students as well as researchers active in the fields of condensed matter physics and materials science in general, particularly those with an interest in correlated metals, frustrated spin systems, superconductivity, and competing orders. Provides a detailed description of sample growth and characterization for correlated and complex materials Features extensive coverage of results from major experimental techniques that probe the electronic and magnetic properties of Fe-based superconductors Offers a comprehensive review of recent theoretical developments in electronic correlation and frustration Represents a one-stop reference for a broad audience from advanced undergraduate and graduate students through active researchers Written by leading experts in each of the relevant sub-fields.

Optics. Quantum optics --- Electromagnetism. Ferromagnetism --- Electronics and optics of solids --- Thermal properties of solids --- Materials sciences --- Electrical engineering --- supergeleiding --- materiaalkennis --- elektronica --- magnetisme --- transistoren --- halfgeleiders --- microwaves

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In this book, the author theoretically studies two aspects of topological states. First, novel states arising from hybridizing surface states of topological insulators are theoretically introduced. As a remarkable example, the author shows the existence of gapless interface states at the interface between two different topological insulators, which belong to the same topological phase. While such interface states are usually gapped due to hybridization, the author proves that the interface states are in fact gapless when the two topological insulators have opposite chiralities. This is the first time that gapless topological novel interface states protected by mirror symmetry have been proposed. Second, the author studies the Weyl semimetal phase in thin topological insulators subjected to a magnetic field. This Weyl semimetal phase possesses edge states showing abnormal dispersion, which is not observed without mirror symmetry. The author explains that the edge states gain a finite velocity by a particular form of inversion symmetry breaking, which makes it possible to observe the phenomenon by means of electric conductivity.

Pure sciences. Natural sciences (general) --- Statistical physics --- Thermal properties of solids --- Solid state physics --- Physics --- Surface chemistry --- oppervlaktechemie --- supergeleiding --- vaste stof --- materie (fysica) --- oppervlakte-onderzoek --- fysica --- fysicochemie --- interfaces

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In this thesis, the pseudogap and the precursor superconducting state, which are of great importance in clarifying the superconductivity mechanism in high-temperature cuprate superconductors, are investigated with a c-axis optical study in YBa2(Cu1-xZnx)3Oy. Testing was performed over a wide energy range with smaller temperature intervals for several Zn-substituted samples, as well as for several carrier-doping levels. A spectral weight (SW) analysis, in which the pseudogap behavior can be separated from the superconducting condensate with the SW transfer to the high-energy region, revealed that the pseudogap is not the precursor of the superconductivity (carriers moving to the high-energy region with pseudogap opening never contribute to the superconducting condensation). Moreover, the high-energy transfer continues even below Tc for the Zn-substituted samples (in which we weaken the superconductivity), which gives evidence to the coexistence of the pseudogap and the superconducting gap below Tc. On the other hand, the analysis of optical conductivity revealed that a precursor state to superconductivity can be defined at temperatures much higher than Tc. The superconducting carrier density (ns) was calculated for each temperature (above and below Tc) and the results confirmed the existence of ns at temperatures above Tc. The observed real superconducting condensate (ns) above Tc puts a serious constraint on the theory for high- Tc superconductivity. A theory based on an inhomogeneous superconducting state, in which a microscopically phase-separated state in a doped Mott insulator can be observed, is the most plausible candidate. This theory can explain the existence of ns and the observed temperature range for the precursor superconducting state. The results obtained show that the pseudogap coexists with superconductivity below Tc and is not the precursor of superconductivity. On the other hand, it is also possible to define a precursor superconducting state that is different than the pseudogap. The temperature range and the observed superconducting condensate in this state can be explained with the help of the inhomogeneous superconducting state.

Mathematical physics --- Thermodynamics --- Electromagnetism. Ferromagnetism --- Thermal properties of solids --- Solid state physics --- Physics --- supergeleiding --- vaste stof --- materie (fysica) --- koude --- wiskunde --- fysica --- magnetisme

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In the second half of the last century solid state physics and materials science experienced a great advance and established itself as an important and independent new field. This book provides an introduction to the fundamentals of solid state physics, including a description of the key people in the field and the historic context. The book concentrates on the electric and magnetic properties of materials. It is written for students up to the bachelor in the fields of physics, materials science, and electric engineering. Because of its vivid explanations and its didactic approach, it can also serve as a motivating pre-stage and supporting companion in the study of the established and more detailed textbooks of solid state physics. The book is suitable for a quick repetition prior to examinations. For his scientific accomplishments, in 1992 the author received the Max-Planck Research Price and in 2001 the Cryogenics Price. He studied physics and mathematics at the University of Marburg, as well at the Technical Universities of Munich and Darmstadt. In 1958 he obtained his PhD in experimental physics at the University of Marburg. After working at the Research Center Karlsruhe and at a research institute near Albany, New York, he worked for 12 years at the Argonne National Laboratory near Chicago, Illinois. In 1974 he accepted an appointment at a chair of Experimental Physics at the University of Tübingen. There he taught and performed research until his retirement in 1999.

Fluid mechanics --- Optics. Quantum optics --- Electronics and optics of solids --- Thermal properties of solids --- Solid state physics --- Spectrometric and optical chemical analysis --- Electronics --- Electrical engineering --- supergeleiding --- vaste stof --- materie (fysica) --- telecommunicatie --- elektronica --- transistoren --- halfgeleiders --- microwaves --- spectrometrie --- optica