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Author : Samuel Patrick Michael Curley
Release : 2021
Genre : Ferromagnetic materials
Kind : eBook
Book Rating : /5 ( reviews)
Book Synopsis Exotic Ground States and Excitations in Quantum Magnets by : Samuel Patrick Michael Curley
Download or read book Exotic Ground States and Excitations in Quantum Magnets written by Samuel Patrick Michael Curley. This book was released on 2021. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Charuni Dissanayake
Release : 2023
Genre :
Kind : eBook
Book Rating : /5 ( reviews)
Book Synopsis Exotic Ground States in Novel Quantum Magnets by : Charuni Dissanayake
Download or read book Exotic Ground States in Novel Quantum Magnets written by Charuni Dissanayake. This book was released on 2023. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Author : Stephen J. Blundell
Release : 2012-06-28
Genre : Body, Mind & Spirit
Kind : eBook
Book Rating : 208/5 ( reviews)
Book Synopsis Magnetism: A Very Short Introduction by : Stephen J. Blundell
Download or read book Magnetism: A Very Short Introduction written by Stephen J. Blundell. This book was released on 2012-06-28. Available in PDF, EPUB and Kindle. Book excerpt: What is that strange and mysterious force that pulls one magnet towards another, yet seems to operate through empty space? This is the elusive force of magnetism. Stephen J. Blundell considers early theories of magnetism, the discovery that Earth is a magnet, and the importance of magnetism in modern technology.
Author : Hyejin Ju
Release : 2013
Genre :
Kind : eBook
Book Rating : 262/5 ( reviews)
Book Synopsis Characterizing Ground States of Low-dimensional Quantum Magnets by : Hyejin Ju
Download or read book Characterizing Ground States of Low-dimensional Quantum Magnets written by Hyejin Ju. This book was released on 2013. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Author : Sarben Sarkar
Release : 2013-11-11
Genre : Science
Kind : eBook
Book Rating : 742/5 ( reviews)
Book Synopsis Exotic States in Quantum Nanostructures by : Sarben Sarkar
Download or read book Exotic States in Quantum Nanostructures written by Sarben Sarkar. This book was released on 2013-11-11. Available in PDF, EPUB and Kindle. Book excerpt: Mesoscopic physics has made great strides in the last few years. It is an area of research that is attractive to many graduate students of theoretical condensed matter physics. The techniques that are needed to understand it go beyond the conventional perturbative approaches that still form the bulk of the graduate lectures that are given to students. Even when the non-perturbative techniques are presented, they often are presented within an abstract context. It is important to have lectures given by experts in the field, which present both theory and experiment in an illuminating and inspiring way, so that the impact of new methodology on novel physics is clear. It is an apt time to have such a volume since the field has reached a level of maturity. The pedagogical nature of the articles and the variety of topics makes it an important resource for newcomers to the field. The topics range from the newly emerging area of quantum computers and quantum information using Josephson junctions to the formal mathematical methods of conformal field theory which are applied to the understanding of Luttinger liquids. Electrons which interact strongly can give rise to non-trivial ground states such as superconductivity, quantum Hall states and magnetism. Both their theory and application are discussed in a pedagogical way for quantum information in mesoscopic superconducting devices, skyrmions and magnetism in two dimensional electron gases, transport in quantum wires, metal-insulator transitions and spin electronics.
