Ground State Properties and Field Induced Phases in Quasi One-dimensional Quantum Magnets

Ground State Properties and Field Induced Phases in Quasi One-dimensional Quantum Magnets PDF Author: Britta Willenberg
Publisher:
ISBN:
Category :
Languages : en
Pages : 174

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Ground State Properties and Field Induced Phases in Quasi One-dimensional Quantum Magnets

Ground State Properties and Field Induced Phases in Quasi One-dimensional Quantum Magnets PDF Author: Britta Willenberg
Publisher:
ISBN:
Category :
Languages : en
Pages : 174

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Exotic Ground States in Novel Quantum Magnets

Exotic Ground States in Novel Quantum Magnets PDF Author: Charuni Dissanayake
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Quantum mechanical frustration (QMF) in magnetic materials has become a pivotal ingredient in discovering intriguing properties of materials. The quantum spin liquid (QSL) state is a prime consequence of frustration in which spin fluctuations persist to absolute zero temperature. This orderless state is not characterized by symmetry breaking and guarantees an infinite degeneracy in its ground state. The quest to realize such nontrivial ground states in view of spin correlation, elementary excitation, topology, and geometry requires convincing experimental evidence. QMF is often manifested in unique lattice systems, such as spin-1/2 hyper-honeycomb lattices with strong spin-orbit coupling and geometrically frustrated Kagome lattices. Metal-organic frameworks (MOFs) that comprise metal ions with organic linkers via coordinate bonds have recently been proposed to realize the QSL ground state. Owing to the vast versatility of constituent's, the copper-oxalate MOF, [(C2H5)3NH]2Cu2(C2O4)3, unfolds a new avenue for us to realize unusual magnetic phases. To investigate the exotic ground state, we synthesized single crystals of [(C2H5)3NH]2Cu2(C2O4)3 and measured their thermodynamic properties. Our low-temperature and high-magnetic-field heat-capacity (Cp) measurements corroborate an exotic but rich ground state in [(C2H5)3NH]2Cu2(C2O4)3. A finite linear-in temperature Cp term with no indication of any thermal anomaly was observed at low temperature in zero field, indicating the absence of magnetic order and the presence of gapless spinon excitations despite the Mott insulating phase. Applied magnetic fields suppress the low-temperature Cp and drive the system into a gapped phase. The field-induced gap is described by the sine-Gorden model for quasi-one-dimensional antiferromagnetic Heisenberg chains, originating from anisotropic magnetic exchange interactions due to the Jahn-Teller distortion. Kagome lattices are archetypes of potential QSL, superconducting, Chern insulating states due to flat energy bands, Dirac fermions, and van Hove singularities in its electronic band structure. Sc3Mn3Al7Si5 is a transition metal compound with a hexagonal structure in which magnetic Mn atoms form kagome nets and does not show magnetic order down to 2 K, suggestive of a possible itinerant QSL. In this dissertation, to elucidate its exotic ground state, we synthesized single crystals of Sc3Mn3Al7Si5 and measured magnetoresistance, Cp, soft point contact spectroscopy, and torque magnetometry at low temperatures and high magnetic fields. Our experimental results suggest that the unusual ground state is induced by dispersionless energy bands induced by strong electron correlations. Our findings through distinct states of matter spanning from Mott insulators to itinerant metals will provide new insights to characterize the ground state in novel quantum magnets.

Ground States of a Two-dimensional Frustrated Quantum Antiferromagent Cs2CuCl4

Ground States of a Two-dimensional Frustrated Quantum Antiferromagent Cs2CuCl4 PDF Author: Younghyun Kim
Publisher:
ISBN:
Category :
Languages : en
Pages : 86

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Book Description
The properties of a frustrated quantum antiferromagnet are interesting topics in condensed matter theory. Among the quantum antiferromagnets, Cs2CuCl4 gains attention as one of the candidates for materials with ground state spin liquid phase. The recent experimental results show that there exist several ground state phases in the presence of magnetic field which cannot be explained with classical Hamiltonian. In the thesis, I numerically studied the ground state of Cs2CuCl4 using a modified classical Hamiltonian, and I compared the result with previous experiments and classical analysis. The resulted magnetic phase diagram contains two phases, cone and ferromagnetic phase, which are separated by second order transition and a first order transition line for intermediate longitudinal field which ends up with a critical point.

Quantum Magnetism

Quantum Magnetism PDF Author: Ulrich Schollwöck
Publisher: Springer
ISBN: 3540400664
Category : Science
Languages : en
Pages : 488

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Book Description
Closing a gap in the literature, this volume is intended both as an introductory text at postgraduate level and as a modern, comprehensive reference for researchers in the field. Provides a full working description of the main fundamental tools in the theorists toolbox which have proven themselves on the field of quantum magnetism in recent years. Concludes by focusing on the most important cuurent materials form an experimental viewpoint, thus linking back to the initial theoretical concepts.

Physics Briefs

Physics Briefs PDF Author:
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 1420

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Magnetic Field Effects in Low-Dimensional Quantum Magnets

Magnetic Field Effects in Low-Dimensional Quantum Magnets PDF Author: Adam Iaizzi
Publisher: Springer
ISBN: 3030018032
Category : Science
Languages : en
Pages : 170

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Book Description
This thesis is a tour-de-force combination of analytic and computational results clarifying and resolving important questions about the nature of quantum phase transitions in one- and two-dimensional magnetic systems. The author presents a comprehensive study of a low-dimensional spin-half quantum antiferromagnet (the J-Q model) in the presence of a magnetic field in both one and two dimensions, demonstrating the causes of metamagnetism in such systems and providing direct evidence of fractionalized excitations near the deconfined quantum critical point. In addition to describing significant new research results, this thesis also provides the non-expert with a clear understanding of the nature and importance of computational physics and its role in condensed matter physics as well as the nature of phase transitions, both classical and quantum. It also contains an elegant and detailed but accessible summary of the methods used in the thesis—exact diagonalization, Monte Carlo, quantum Monte Carlo and the stochastic series expansion—that will serve as a valuable pedagogical introduction to students beginning in this field.

High Field Magnetism

High Field Magnetism PDF Author: M. Date
Publisher: Elsevier
ISBN: 0444599193
Category : Technology & Engineering
Languages : en
Pages : 359

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Book Description
High Field Magnetism presents the proceedings of the International Symposium on High Field Magnetism held at the Osaka University and Hotel Plaza in Osaka on September 13-14, 1982 as a satellite symposium of the International Conference on Magnetism-1982-Kyoto. The symposium tackled a wide variety of high field generation methods and material systems, with magnetism orientation as the main objective. A special Technical Exposition was held in the poster session where representatives from MIT, Grenoble, and other high field facilities were invited to give a descriptive review of each laboratory. This book is divided into eight parts, beginning with an introductory chapter into the subject of high field magnetism. The succeeding parts focus on magnetic interactions and phase transitions in high magnetic fields; metals and alloys in high magnetic fields; high field superconductivity; spin and charge fluctuations in high magnetic fields; high field magneto-optics; high field magnetic resonance; and high magnetic field facilities and techniques. This book will be of interest to practitioners in the fields of cryogenic engineering and applied physics.

Characterizing Ground States of Low-dimensional Quantum Magnets

Characterizing Ground States of Low-dimensional Quantum Magnets PDF Author: Hyejin Ju
Publisher:
ISBN: 9781303052262
Category :
Languages : en
Pages : 196

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Book Description
The study of frustration in quantum magnetism has been the focus of extensive research in the past couple of decades. The class of materials in this category is typically strongly correlated, due to strong electron-electron repulsion. In one- and two-dimensions, quantum fluctuations dominate these systems, and often, semi-classical approximations become an oversimplification. This thesis is concerned with exploring exotic physics that can emerge in low-dimensional quantum magnets. First, we use a T = 0 projected Monte Carlo algorithm in the valence bond basis to study the entanglement scaling of two-dimensional (2d) gapless systems. In particular, we focus on the resonating-valence-bond wavefunction as well as the gapless Goldstone mode in the Heisenberg model on the square lattice. We find that, in addition to the area law, there is a subleading, shape-dependent piece to the entanglement entropy, which is reminiscent of one dimensional (1d) gapless systems. We then explore the Heisenberg model under an applied magnetic field on the quasi-1d problem of a three-leg triangular spin tube (TST), using extensive density-matrix-renormalization group calculations coupled with analytical arguments to describe the results. We find that the physics describing this model differs from some of the well-known results on the two dimensional lattice, especially near low magnetic fields and at 1/3 magnetization. Finally, further research and possibilities in numerical techniques are discussed.

Introduction to Frustrated Magnetism

Introduction to Frustrated Magnetism PDF Author: Claudine Lacroix
Publisher: Springer Science & Business Media
ISBN: 3642105890
Category : Science
Languages : en
Pages : 682

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Book Description
The field of highly frustrated magnetism has developed considerably and expanded over the last 15 years. Issuing from canonical geometric frustration of interactions, it now extends over other aspects with many degrees of freedom such as magneto-elastic couplings, orbital degrees of freedom, dilution effects, and electron doping. Its is thus shown here that the concept of frustration impacts on many other fields in physics than magnetism. This book represents a state-of-the-art review aimed at a broad audience with tutorial chapters and more topical ones, encompassing solid-state chemistry, experimental and theoretical physics.

Low Temperature Physics

Low Temperature Physics PDF Author: Y. Takano
Publisher: American Institute of Physics
ISBN: 9780735403475
Category : Technology & Engineering
Languages : en
Pages : 772

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Book Description
This book represents recent cutting-edge developments in low temperature physics, reported at one of the largest international conferences in physics. The subjects covered are superconductivity, magnetism, quantum gases, quantum liquids and solids, electronic properties of solids, low-temperature experimental techniques, cryogenics, and applications.