Low Dimensional Systems

This volume contains papers presented at the NATO Advanced Research Workshop (ARW) Dynamic Interactions in Quantum Dot Systems held at Hotel Atrium in Puszczykowo, near Poznan, Poland, May 16-19,2002. The term low-dimensional systems, which is used in the title of this volume, refers to those systems which contain at least one dimension that is intermediate between those characteristic ofatoms/molecules and those ofthe bulk material. Depending on how many dimensions lay within this range, we generally speak of quantum wells, quantum wires, and quantum dots. As such an intermediate state, some properties of low-dimensional systems are very different to those of their molecular and bulk counterparts. These properties generally include optical, electronic, and magnetic properties, and all these are partially covered in this book. The main goal of the workshop was to discuss the actual state of the art in the broad area ofnanotechnology. The initial focus was on the innovative synthesis of nanomaterials and their properties such as: quantum size effects, superparamagnetism, or field emission. These topics lead us into the various field based interactions including plasmon- magnetic spin- and exciton coupling. The newer, more sophisticated methods for characterization of nanomaterials were discussed, as well as the methods for possible industrial applications. In general, chemists and physicists, as well as experts on both theory and experiments on nanosized regime structures were brought together, to discuss the general phenomena underlying their fields ofinterest from different points ofview.

Experimental progress over the past few years has made it possible to test a n- ber of fundamental physical concepts related to the motion of electrons in low dimensions. The production and experimental control of novel structures with typical sizes in the sub-micrometer regime has now become possible. In parti- lar, semiconductors are widely used in order to con?ne the motion of electrons in two-dimensional heterostructures. The quantum Hall e?ect was one of the ?rst highlights of the new physics that is revealed by this con?nement. In a further step of the technological development in semiconductor-heterostructures, other arti?cial devices such as quasi one-dimensional ‘quantum wires’ and ‘quantum dots’ (arti?cial atoms) have also been produced. These structures again di?er very markedly from three- and two-dimensional systems, especially in relation to the transport of electrons and the interaction with light. Although the technol- ical advances and the experimental skills connected with these new structures are progressing extremely fast, our theoretical understanding of the physical e?ects (such as the quantum Hall e?ect) is still at a very rudimentary level. In low-dimensional structures, the interaction of electrons with one another and with other degrees of freedoms such as lattice vibrations or light gives rise to new phenomena that are very di?erent from those familiar in the bulk ma- rial. The theoretical formulation of the electronic transport properties of small devices may be considered well-established, provided interaction processes are neglected.

Filling the gap for comprehensive coverage of the realistic fundamentals and approaches needed to perform cutting-edge research on mesoscopic systems, this textbook allows advanced students to acquire and use the skills at a highly technical, research-qualifying level. Starting with a brief refresher to get all readers on an equal footing, the text moves on to a broad selection of advanced topics, backed by problems with solutions for use in classrooms as well as for self-study. Written by authors with research and teaching backgrounds from eminent institutions and based on a tried-and-tested lecture, this is a must-have for researchers, research students and instructors involved with semiconductor junctions, nanostructures and thin film systems.

The physics of strongly correlated fermions and bosons in a disordered envi ronment and confined geometries is at the focus of intense experimental and theoretical research efforts. Advances in material technology and in low temper ature techniques during the last few years led to the discoveries of new physical of atomic gases and a possible metal phenomena including Bose condensation insulator transition in two-dimensional high mobility electron structures. Situ ations were the electronic system is so dominated by interactions that the old concepts of a Fermi liquid do not necessarily make a good starting point are now routinely achieved. This is particularly true in the theory of low dimensional systems such as carbon nanotubes, or in two dimensional electron gases in high mobility devices where the electrons can form a variety of new structures. In many of these sys tems disorder is an unavoidable complication and lead to a host of rich physical phenomena. This has pushed the forefront of fundamental research in condensed matter towards the edge where the interplay between many-body correlations and quantum interference enhanced by disorder has become the key to the understand ing of novel phenomena.

This book discusses the essential properties of carbon nanotubes and 2D graphene systems. The book focuses on the fundamental excitation properties of a large range of graphene-related materials, presenting a new theoretical framework that couples electronic properties and e-e Coulomb interactions together in order to thoroughly explore Coulomb excitations and decay rates in carbon-nanotube-related systems. This book is aimed at researchers in nanomaterials and high-level students in physics, science and material engineering. It will serve as the ideal reference text for scientists working on carbon nanotubes, and will thoroughly expand the reader's knowledge of the application of carbon nanotube technology to graphene-based materials and the technological potential thereof. Key Features:  Covers many graphene-related systems, such as, 1D-3D carbon nanotube systems, layered graphenes, and other 2D materials. Presents a generalized theoretical model for essential excitation properties. Presents comprehensive theoretical results for fundamental and applied sciences. Presents reliable and complete results in the diversified many-body properties. Provides potential applications for graphene-based electronic and plasmonic devices.

The composition of modern semiconductor heterostructures can be controlled precisely on the atomic scale to create low-dimensional systems. These systems have revolutionised semiconductor physics, and their impact on technology, particularly for semiconductor lasers and ultrafast transistors, is widespread and burgeoning. This book provides an introduction to the general principles that underlie low-dimensional semiconductors. As far as possible, simple physical explanations are used, with reference to examples from actual devices. The author shows how, beginning with fundamental results from quantum mechanics and solid-state physics, a formalism can be developed that describes the properties of low-dimensional semiconductor systems. Among numerous examples, two key systems are studied in detail: the two-dimensional electron gas, employed in field-effect transistors, and the quantum well, whose optical properties find application in lasers and other opto-electronic devices. The book includes many exercises and will be invaluable to undergraduate and first-year graduate physics or electrical engineering students taking courses in low-dimensional systems or heterostructure device physics.

This book focuses on the fundamental phenomena at nanoscale. It covers synthesis, properties, characterization and computer modelling of nanomaterials, nanotechnologies, bionanotechnology, involving nanodevices. Further topics are imaging, measuring, modeling and manipulating of low dimensional matter at nanoscale. The topics covered in the book are of vital importance in a wide range of modern and emerging technologies employed or to be employed in most industries, communication, healthcare, energy, conservation , biology, medical science, food, environment, and education, and consequently have great impact on our society.

This book contains contributions on some of the most important and current topics on the physics of low dimensional systems. The main emphasis is on the magnetic properties of surfaces, thin films, and atomic clusters. State-of-the-art techniques are discussed in detail. Techniques for the production and measurement of nanostructures are discussed, and pioneering contributions on the effect on health of these particles are presented. Important studies on semiconductor nanostructures are addressed as well as aerosol systems.