Disorder Induced Metal Insulator Transition in Anisotropic Systems

Disorder Induced Metal Insulator Transition in Anisotropic Systems PDF Author: Frank Milde
Publisher:
ISBN:
Category :
Languages : en
Pages : 105

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Disorder Induced Metal Insulator Transition in Anisotropic Systems

Disorder Induced Metal Insulator Transition in Anisotropic Systems PDF Author: Frank Milde
Publisher:
ISBN:
Category :
Languages : en
Pages : 105

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Book Description


Disorder-induced Metal-insulator Transition in Anisotropic Systems

Disorder-induced Metal-insulator Transition in Anisotropic Systems PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Untersucht wird der Auswirkung von Anisotropie auf den unordnungsinduzierten Metall-Isolator-Übergang (MIÜ) im Rahmen des dreidimensionalen Anderson-Modells der Lokalisierung für (schwach) gekoppelte Ebenen bzw. Ketten. Mittels numerischer Verfahren (Lanczos- und Transfer-Matrix-Methode) werden Eigenwerte und -vektoren bzw. die Lokalisierungslänge berechnet. Zur Bestimmung des kritischen Exponenten dieses Phasenüberganges 2. Ordnung wird ein allgemeiner Skalenansatz verwendet, der auch den Einfluss einer irrelevanten Skalenvariablen und Nichtlinearitäten berücksichtigt. Ein Kapitel untersucht die verwendeten numerischen Verfahren, verschiedene Methoden werden verglichen und die Portierbarkeit zu Parallelrechnern diskutiert. Der MIÜ wird mit zwei unabhängigen Methoden charakterisiert: Eigenwertstatistik und Transfer-Matrix-Methode. Die Systemgrößenunabhängigkeit der betrachteten Größen am Phasenübergang wird benutzt um den MIÜ zu identifizieren. Sie resultiert aus der Multifraktalität der kritischen Eigenzustände, die für den isotropen Fall bis zu einer Systemgröße von 111^3 Gitterplätzen gezeigt wird. Es stellt sich heraus, daß der MIÜ auch bei sehr starker Anisotropie existiert und bereits bei geringerer Potentialunordnung als im isotropen Fall auftritt. Für den Fall sehr schwach gekoppelter Ebenen wird gezeigt, daß der kritische Exponent mit dem des isotropen Falles übereinstimmt und damit die übliche Einteilung in Universalitätsklassen bestätigt.

Localization and Metal-Insulator Transitions

Localization and Metal-Insulator Transitions PDF Author: Hellmut Fritzche
Publisher: Springer Science & Business Media
ISBN: 146132517X
Category : Science
Languages : en
Pages : 529

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Book Description
This volume and its two companion volumes, entitled Tetrahedrally-Bonded Amorphous Semiconductors and Physics of Disordered Materials, are our way of paying special tribute to Sir Nevill Mott and to express our heartfelt wishes to him on the occasion of his eightieth birthday. Sir Nevill has set the highest standards as a physicist, teacher, and scientific leader. Our feelings for him include not only the respect and admiration due a great scientist, but also a deep affection for a great human being, who possesses a rare combination of outstanding personal qualities. We thank him for enriching our lives, and we shall forever carry cherished memories of this noble man. Scientists best express their thanks by contributing their thoughts and observations to a Festschrift. This one honoring Sir Nevill fills three volumes, with literally hundreds of authors meeting a strict deadline. The fact that contributions poured in from all parts of the world attests to the international cohesion of our scientific community. It is a tribute to Sir Nevill's stand for peace and understanding, transcending national borders. The editors wish to express their gratitude to Ghazaleh Koefod for her diligence and expertise in deciphering and typing many of the papers, as well as helping in numerous other ways. The blame for the errors that remain belongs to the editors.

Computational Statistical Physics

Computational Statistical Physics PDF Author: K.-H. Hoffmann
Publisher: Springer Science & Business Media
ISBN: 3662048043
Category : Science
Languages : en
Pages : 312

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Book Description
In recent years statistical physics has made significant progress as a result of advances in numerical techniques. While good textbooks exist on the general aspects of statistical physics, the numerical methods and the new developments based on large-scale computing are not usually adequately presented. In this book 16 experts describe the application of methods of statistical physics to various areas in physics such as disordered materials, quasicrystals, semiconductors, and also to other areas beyond physics, such as financial markets, game theory, evolution, and traffic planning, in which statistical physics has recently become significant. In this way the universality of the underlying concepts and methods such as fractals, random matrix theory, time series, neural networks, evolutionary algorithms, becomes clear. The topics are covered by introductory, tutorial presentations.

Studies of High Temperature Superconductors

Studies of High Temperature Superconductors PDF Author: A. V. Narlikar
Publisher: Nova Publishers
ISBN: 9781560721321
Category : Technology & Engineering
Languages : en
Pages : 476

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Book Description
Six papers by physicists from the Japan, India, Brazil and the US address some of the broad frontal issues of superconductivity, which include the mechanisms of high-temperature superconductivity, extra-high-temperature phenomena, the normal state pseudogap, the observations of the isotope effect in a host of different superconducting systems and their explanations, and the unusual features of strongly correlated electron systems like heavy fermions. Two extended papers explore the importance of positron annihilation and using electron spin resonance techniques to study superconducting materials. The treatments should be accessible to working scientists and engineers and to graduate students of physics, chemistry, materials science, solid-state electronics, and other disciplines.

Superconductivity and Localization

Superconductivity and Localization PDF Author: M. V. Sadovski?
Publisher: World Scientific
ISBN: 9810241933
Category : Science
Languages : en
Pages : 271

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Book Description
This book presents a review of theoretical and experimental work on the problem of the interplay of Anderson localization and superconductivity in strongly disordered systems. Superconductivity persists close to disorder-induced metal-insulator transition in a number of real systems, e.g. amorphous metals and compounds, systems disordered by fast neutron irradiation, systems with impurities, etc. High temperature superconductors are especially interesting from this point of view, as the experiments with controllable disordering may provide important clues to the nature of electronic states in these systems.The book starts with a brief discussion on modern aspects of localization theory, including the basic concept of scaling, self-consistent theory of localization and interaction effects. After that it analyzes disorder effects on Cooper pairing and superconductivity transition temperature as well as Ginzburg-Landau equations for superconductors that are close to the Anderson transition. A necessary generalization of the usual theory of dirty superconductors is formulated which allows one to analyze anomalies of the main superconducting properties close to disorder-induced metal-insulator transition. Finally, the book reviews a number of experiments demonstrating superconductivity close to the Anderson transition, in both traditional and high c superconductors."

Anisotropic Phase Separation Through the Metal-insulator Transition in Amorphous Mo-Ge and Fe-Ge Alloys

Anisotropic Phase Separation Through the Metal-insulator Transition in Amorphous Mo-Ge and Fe-Ge Alloys PDF Author: Michael J. Regan
Publisher:
ISBN:
Category :
Languages : en
Pages : 340

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The Mott Metal-Insulator Transition

The Mott Metal-Insulator Transition PDF Author: Florian Gebhard
Publisher: Springer
ISBN: 3540148582
Category : Technology & Engineering
Languages : en
Pages : 318

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Book Description
Little do we reliably know about the Mott transition, and we are far from a complete understanding of the metal --insulator transition due to electr- electron interactions. Mott summarized his basic ideas on the subject in his wonderful book Metal--Insulator nansitions that first appeared in 1974 11. 1). In his view, a Motk insulator displays a gap for charge-carrying excitations due to electron cowelations, whose importance is expressed by the presence of local magnetic moments regardless of whether or not they are ordered. Since the subject is far from being settled, different opinions on specific aspects of the Mott transition still persist. This book naturally embodies my own understanding of the phenomenon, inspired by the work of the late Sir Kevill Mott. The purpose of this book is twofold: first, to give a detailed presen- tion of the basic theoretical concopts for Mott insulators and, second, to test these ideas against the results from model calculations. For this purpose the Hubbard model and some of its derivatives are best suited. The Hubbard model describes a Mott transition with a mere minimum of tunable par- eters, and various exact statements and even exact solutions exist in certain limiting cases. Exact solutions not only allow us to test our basic ideas, but also help to assess the quality of approxin~ate theories for correlated electron systems.

Journal of Experimental and Theoretical Physics

Journal of Experimental and Theoretical Physics PDF Author:
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 432

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The Metal-Nonmetal Transition Revisited

The Metal-Nonmetal Transition Revisited PDF Author: P. Edwards
Publisher: CRC Press
ISBN: 1482272717
Category : Technology & Engineering
Languages : en
Pages : 439

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Book Description
This text surveys the various aspects of the fundamental problem related to the metallic and non-metallic states of matter, a question physicists have been studying for almost 100 years. The book poses questions and challenges in this area, as well as highlighting present understandings of the topic. Topics covered by the book include physics of dense ionized metal plasmas; metallic hydrogen; pressure-induced metallization; the M-I transition in doped semiconductors; transport studies in doped semiconductors near the metal-insulator transition; new results in old oxides; metal-insulator transition in 3d transition metal perovskite oxides investigated by high-energy spectroscopies; alkali metal-alkali halide melts; hopping conductivity in granular metals revisited; superconductor-insulator transition in cuprates; molecular metals and superconductors; shear induced chemical reactivity; shear, co-ordination and metallization; quantum diffusion and decoherence; the Mott transition; recent results, more and surprises; Mott-Hubbard-Anderson models.