Phase Transitions in Two-dimensional Systems and Disordered Magnets PDF Download

Author: Robert Alan Pelcovits
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Subir Sachdev
Publisher: Cambridge University Press
ISBN: 113950021X
Category : Science
Languages : en
Pages : 521

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Describing the physical properties of quantum materials near critical points with long-range many-body quantum entanglement, this book introduces readers to the basic theory of quantum phases, their phase transitions and their observable properties. This second edition begins with a new section suitable for an introductory course on quantum phase transitions, assuming no prior knowledge of quantum field theory. It also contains several new chapters to cover important recent advances, such as the Fermi gas near unitarity, Dirac fermions, Fermi liquids and their phase transitions, quantum magnetism, and solvable models obtained from string theory. After introducing the basic theory, it moves on to a detailed description of the canonical quantum-critical phase diagram at non-zero temperatures. Finally, a variety of more complex models are explored. This book is ideal for graduate students and researchers in condensed matter physics and particle and string theory.

Author: Vladimir Dobrosavljevic
Publisher: Oxford University Press
ISBN: 0199592594
Category : Science
Languages : en
Pages : 583

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When many particles come together how do they organize themselves? And what destroys this organization? Combining experiments and theory, this book describes intriguing quantum phases - metals, superconductors and insulators - and transitions between them. It captures the excitement and the controversies on topics at the forefront of research.

Author: Fawaz Y. Hrahsheh
Publisher:
ISBN:
Category : Ferromagnetism
Languages : en
Pages : 146

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"Disorder can have a wide variety of consequences for the physics of phase transitions. Some transitions remain unchanged in the presence of disorder while others are completely destroyed. In this thesis we study the effects of disorder on several classical and quantum phase transitions in condensed matter systems. After a brief introduction, we study the ferromagnetic phase transition in a randomly layered Heisenberg magnet using large-scale Monte-Carlo simulations. Our results provide numerical evidence for the exotic infinite-randomness scenario. We study classical and quantum smeared phase transitions in substitutional alloys A[subscript 1-x]B[subscript x]. Our results show that the disorder completely destroys the phase transition with a pronounced tail of the ordered phase developing for all compositions x

Author: Yurij Holovatch
Publisher: World Scientific
ISBN: 9811216231
Category : Science
Languages : en
Pages : 294

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Book Description
This book is the sixth volume of reviews on advanced problems of phase transitions and critical phenomena, with the first five volumes appearing in 2004, 2007, 2012, 2015, and 2018. It aims to provide an overview of those aspects of criticality and related topics that have attracted much attention due to the recent contributions. The six chapters discuss criticality of complex systems, where the new, emergent properties appear via collective behaviour of simple elements. Since all complex systems involve cooperative behaviour between many interconnected components, the field of phase transitions and critical phenomena provides a very natural conceptual and methodological framework for their study.As for the previous volumes, this book is based on the review lectures that were given in Lviv (Ukraine) at the 'Ising lectures' — a traditional annual workshop on phase transitions and critical phenomena which aims to bring together scientists working in the field of phase transitions with university students and those who are interested in the topic.The level of presentation makes the book readable both for professionals and the students in the field. On a larger scale, the book may contribute to promoting and deepening studies of phase transitions and critical phenomena.

Author: Lily Joy Stanley
Publisher:
ISBN:
Category : Condensed matter
Languages : en
Pages : 0

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Strongly correlated materials manifest some of the most intriguing behaviors found in condensed matter physics. However, their understanding remains a challenge because they cannot be described using standard theoretical approaches, as such systems are complex and typically have many competing degrees of freedom. Many strongly correlated systems are realized in layered or highly anisotropic materials, and they behave as effectively two-dimensional systems. When the dimensionality is reduced, fluctuations due to the competition between degrees of freedom are more pronounced and easier to observe. Anomalous transport properties are one of the hallmarks of strongly correlated materials; thus, charge transport measurements have proven remarkably effective for their study. This thesis focuses on three very different two-dimensional (2D) materials using charge transport to understand the origin of some of the observed behaviors. The electron system (ES) in Si metal-oxide-semiconductor field-effect transistors (MOSFETs) is a model strongly correlated system with only the interplay of Coulomb interactions and disorder. The insight from this simple system can help to build a more general picture of strongly correlated materials. Second, atomically thin layers of WSe2 produce a unique 2D system to study the universality of the correlated phenomena observed in Si MOSFETs. Finally, the Cu-O planes of La-214 compounds with charge and spin stripe order are complex materials, which behave effectively as 2D, with the interplay of many orders. By varying the dopant of the La-214 compound, the origin of the correlated behaviors can be probed. In the first two materials, the 2D MIT is controlled by applying a gate voltage. The existence of the 2D MIT is supported by an abundance of experimental data but remains poorly understood. Within experimental systems, both electron-electron interactions and disorder are present; however, the theory of their interplay is not fully developed. Studies performed on highly disordered Si MOSFETs suggest the importance of Coulomb interactions for the glassy dynamics observed at low electron densities. Therefore, the first study discussed in this thesis explores relaxations of conductivity in a strongly disordered 2DES with screened Coulomb interactions after the system is quenched-revealing the necessity of long-range Coulomb interactions for the existence of the collective (glassy) relaxation dynamics. Additionally, we have shown that, in the 2DES of the Si MOSFET weakly thermally coupled to the environment, abnormally long relaxations are observed in the presence of short-range interactions, suggesting that the system is in the proximity to a many-body-localized phase. Thus our results also demonstrate a promising new platform for exploring the breakdown of thermalization and MBL in real materials. Evidence of quantum criticality associated with the MIT has been almost exclusively studied in Si MOSFETs. Our second study reveals quantum criticality in WSe2 field-effect transistors showing that transition metal dichalcogenides are viable systems for the low-temperature investigation of the 2D MIT. Our scaling analysis found that the critical exponents agree with those found in low-disordered Si MOSFETs in the presence of local magnetic moments. These findings pave the way for further studies of the fundamental quantum mechanical properties of 2D transition metal dichalcogenides. The final study focuses on fluctuations of charge order (CO) and the magnetoresistance (MR) of stripe-ordered La-214 cuprates. The dynamics of CO are thought to be relevant for the unconventional properties of the normal state and high-temperature superconductivity. We report observations of dynamic charge stripes close to the charge order (and structural) transition in response to temperature perturbations but absent in magnetic field in La1.875Ba0.125CuO4. These dynamic behaviors are only observed when the transition is approached from the charge-ordered state. Additionally, a comparative analysis of the MR of several La-214 single crystals is presented to establish which behaviors are characteristic of the family of materials as opposed to dopant specific. Together, these three studies contribute to understanding the complex interplay of orders found in strongly correlated materials.

Author: Lars Brink
Publisher: World Scientific
ISBN: 9813271353
Category : Science
Languages : en
Pages : 263

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Geometry and topology have been a fascination in physics since the start of the 20th century. A leading example is Einstein's geometrical theory of gravity. At the beginning of the 1970s, topological ideas entered areas of condensed matter physics. These advances were driven by new seminal ideas resolving a serious contradiction between experiment and the standard interpretation of a rigorous mathematical theorem which led to the study of new exotic topological phases of matter. Topological defect driven phase transitions in thin, two dimensional films of superfluids, superconductors and crystals have provided great insight into the mechanism governing these topological phases present in those physical systems. Moreover, many of these topological properties remain 'protected' against disorder and topological distortion perturbations. An example of possible applications of such robustness to perturbations is in the search for encoding information in quantum computers, potentially providing the platform for fault-tolerant quantum computations.In the past four decades, the discovery of topological phases engendered great interest in condensed matter physics. It also attracted the attention of researchers working on quantum information, quantum materials and simulations, high energy physics and string theory. This unique volume contains articles written by some of the most prominent names in the field, including Nobel Laureate John Michael Kosterlitz and Professor Jorge V José. They originate from talks and discussions by leading experts at a recent workshop. They review previous works as well as addressing contemporary developments in the most pressing and important issues on various aspects of topological phases and topological phase transitions.

Author:
Publisher: Elsevier
ISBN: 0080538754
Category : Science
Languages : en
Pages : 337

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Book Description
The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. No longer an area of specialist interest, it has acquired a central focus in condensed matter studies. The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable information on important recent developments.The two review articles in this volume complement each other in a remarkable way. Both deal with what might be called the modern geometricapproach to the properties of macroscopic systems. The first article by Georgii (et al.) describes how recent advances in the application ofgeometric ideas leads to a better understanding of pure phases and phase transitions in equilibrium systems. The second article by Alava (et al.)deals with geometrical aspects of multi-body systems in a hands-on way, going beyond abstract theory to obtain practical answers. Thecombination of computers and geometrical ideas described in this volume will doubtless play a major role in the development of statisticalmechanics in the twenty-first century.

Author: Ali Yazdani
Publisher:
ISBN:
Category :
Languages : en
Pages : 292

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Author: Moshe Gitterman
Publisher: World Scientific Publishing Company
ISBN: 9813106352
Category : Science
Languages : en
Pages : 145

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Book Description
This book presents a short, fairly simple course on the basic theory of phase transitions and its modern applications. In physics, these applications include such modern developments as Bose-Einstein condensation of atoms, high temperature superconductivity, and vortices in superconductors, while in other fields they include small world phenomena and scale-free systems (such as stock markets and the Internet). The advantage of treating all these topics together lies in showing their connection with one another and with the general theory of phase transitions.