The author develops the effective-mass theory of excitons in low-dimensional semiconductors and describes numerical methods for calculating the optical absorption including Coulomb interaction, geometry, and external fields. The theory is applied to Fano resonances in low-dimensional semiconductors and the Zener breakdown in superlattices. Comparing theoretical results with experiments, the book is essentially self-contained; it is a hands-on approach with detailed derivations, worked examples, illustrative figures, and computer programs. The book is clearly structured and will be valuable as an advanced-level self-study or course book for graduate students, lecturers, and researchers.
Self-Trapped Excitons discusses the structure and evolution of the self-trapped exciton (STE) in a wide range of materials. It includes a comprehensive review of experiments and extensive tables of data. Emphasis is given throughout to the unity of the basic physics underlying various manifestations of self-trapping, with the theory being developed from a localized, atomistic perspective. The topics treated in detail in relation to STE relaxation include spontaneous symmetry breaking, lattice defect formation, radiation damage, and electronic sputtering.
Bose-Einstein condensation of excitons is a unique effect in which the electronic states of a solid can self-organize to acquire quantum phase coherence. The phenomenon is closely linked to Bose-Einstein condensation in other systems such as liquid helium and laser-cooled atomic gases. This is the first book to provide a comprehensive survey of this field, covering theoretical aspects as well as recent experimental work. After setting out the relevant basic physics of excitons, the authors discuss exciton-phonon interactions as well as the behaviour of biexcitons. They cover exciton phase transitions and give particular attention to nonlinear optical effects including the optical Stark effect and chaos in excitonic systems. The thermodynamics of equilibrium, quasi-equilibrium, and nonequilibrium systems are examined in detail. The authors interweave theoretical and experimental results throughout the book, and it will be of great interest to graduate students and researchers in semiconductor and superconductor physics, quantum optics, and atomic physics.
This book bridges a gap between two major communities of Condensed Matter Physics, Semiconductors and Superconductors, that have thrived independently. Using an original perspective that the key particles of these materials, excitons and Cooper pairs, are composite bosons, the authors raise fundamental questions of current interest: how does the Pauli exclusion principle wield its power on the fermionic components of bosonic particles at a microscopic level and how this affects their macroscopic physics? What can we learn from Wannier and Frenkel excitons and from Cooper pairs that helps us understand "bosonic condensation" of composite bosons and its difference from Bose-Einstein condensation of elementary bosons? The authors begin with a solid mathematical and physical foundation to derive excitons and Cooper pairs. They further introduce Shiva diagrams as a graphic support to grasp the many-body physics induced by fermion exchange in the absence of fermion-fermion interaction - a novel mechanism not visualized by standard Feynman diagrams. Advanced undergraduate or graduate students in physics with no specific background will benefit from this book. The developed concepts and formalism should also be useful for current research on ultracold atomic gases and exciton-polaritons, and quantum information.
This book presents the various types of resonance effects on excitons, biexcitons and the local electronic centers (LEC) in solids, such as paramagnetic and paraelectric resonances on excitons, exciton acoustic resonance at intra- and interband transitions, radio-optical double resonance on excitons, hole-nuclear double resonance on localized biexcitons, ENDOR and acoustic ENDOR on LEC. The criteria for the generation of coherent photons, phonons and magnons by excitons are explained. The interactions of excitons and biexcitons with paramagnetic centers and nuclear spins, the indirect interaction between the PC through a field of excitons as well as the quasienergy spectrum of excitons and spin systems are discussed. It is proved that the interaction of paramagnetic centers with excitons increases the spin relaxation rate of paramagnetic centers in comparison with the case of their interaction with free carriers. The giant magneto-optical effects in semi-magnetic semiconductors are theoretically interpreted. In recent years, a new perspective has been added to these systems and their interactions: They can be used for storing and processing information in the form of quantum bits (qubits), the building blocks of quantum computers. The basics of this emerging technology are explained and examples of demonstration-type quantum computers based on localized spins in solids are discussed.
This reference book explains the fundamentals of Bose Einstein Condensation (BEC) in excitons and polaritons. It presents five chapters exploring fundamental concepts and recent developments on the subject. Starting with a historical overview of BEC, the book progresses into the origins and behaviors of excitons and polaritons. Chapters also cover the unique thermalization and relaxation kinetics of excitons, and the distinctive features of polaritons, such as lasing, superfluidity, and quantized vortices. The chapters dedicated to BEC in excitons and polaritons detail experimental techniques, theoretical modeling, recent advancements, and practical applications in a simplified way for beginners. This book serves as a resource for researchers, physicists, and students interested in the phenomena of BEC, providing insights into both the theoretical foundations and the practical implications of excitons and polaritons.
Dynamics of Molecular Excitons provides a comprehensive, but concise description of major theories on the dynamics of molecular excitons, intended to serve as a self-contained resource on the topic. Designed to help those new to this area gain proficiency in this field, experts will also find the book useful in developing a deeper understanding of the subject. The starting point of the book is the standard microscopic definition of molecular Hamiltonians presented in commonly accepted modern quantum mechanical notations. Major assumptions and approximations involved in constructing Frenkel-type exciton Hamiltonians, which are well established, but are often hidden under arcane notations and approximations of old publications, are presented in detail. This will help quantum chemists understand the major assumptions involved in the definition of commonly used exciton models. Rate theories of exciton dynamics, such as Förster and Dexter theories and their modern generalizations, are presented in a unified and detailed manner. In addition, important aspects that are often neglected, such as local field effect and the role of fluctuating environments, are discussed. Various quantum dynamics methods allowing coherent dynamics of excitons are presented in a systematic manner in the context of quantum master equations or path integral formalisms. The author also provides a detailed theoretical explanation for the major spectroscopic techniques probing exciton dynamics, including modern two-dimensional electronic spectroscopy, with a critical assessment of the implications of these spectroscopic measurements. Finally, the book includes a brief overview of major applications including an explanation of organic photovoltaic materials and natural light harvesting complexes. - Covers major theories of exciton dynamics in a consciously concise and easily readable way - Bridges the gap between quantum dynamics working with phenomenological exciton Hamiltonian and quantum chemistry construct reliable models amenable for dynamics calculations from ab initio calculations - Explores modern nonlinear electronic spectroscopy techniques to probe exciton dynamics, showing how it is applied
Excitons are considered as the basic concept used by describing the spectral properties of photosynthetic pigment-protein complexes and excitation dynamics in photosynthetic light-harvesting antenna and reaction centers. Following the recently obtained structures of a variety of photosynthetic pigment-protein complexes from plants and bacteria our interest in understanding the relation between structure, function and spectroscopy has strongly increased. These data demonstrate a short interpigment distance (of the order of 1 nm or even smaller) and/or a highly symmetric (ring-like) arrangement of pigment molecules in peripheral light-harvesting complexes of photosynthetic bacteria. Books which were devoted to the exciton problem so far mainly considered the spectral properties of molecular crystals. However, the small size of these pigment aggregates in the pigment-protein complexes as well as the role of the protein, which is responsible for the structural arrangement of the complex, clearly will have a dramatic influence on the pigment spectra and exciton dynamics. All these aspects of the problem are considered in this book. Exciton theory is mainly considered for small molecular aggregates (dimers, ring-like structures etc.). Together with the theoretical description of the classical conceptual approach, which mainly deals with polarization properties of the absorption and fluorescence spectra, the nonlinear femtosecond spectroscopy which is widely used for investigations now is also discussed. A large part of the book demonstrates the excitonic effects in a multitude of photosynthetic pigment-protein complexes and how we can understand these properties on the basis of the exciton concept.
