Download or read book Angle Resolved Photoemission Spectroscopy Study of Spin Fluctuations in the Cuprate Superconductors written by Francisco Restrepo and published by Springer Nature. This book was released on 2022-09-13 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis makes significant advances towards an understanding of superconductivity in the cuprate family of unconventional, high-temperature superconductors. Even though the high-temperature superconductors were discovered over 35 years ago, there is not yet a general consensus on an acceptable theory of superconductivity in these materials. One of the early proposals suggested that collective magnetic excitations of the conduction electrons could lead them to form pairs, which in turn condense to form the superconducting state at a critical temperature Tc. Quantitative calculations of Tc using experimental data were, however, not available to verify the applicability of this magnetic mechanism. In this thesis, the author constructed an angle-resolved photoemission apparatus that could provide sufficiently accurate data of the electronic excitation spectra of samples in the normal state, data which was furthermore unusually devoid of any surface contamination. The author also applied the Bethe-Salpeter method to his uncommonly pristine and precise normal state data, and was able to predict the approximate superconducting transition temperatures of different samples. This rare combination of experiment with sophisticated theoretical calculations leads to the conclusion that antiferromagnetic correlations are a viable candidate for the pairing interaction in the cuprate superconductors.

Download or read book Photoemission Spectroscopy on High Temperature Superconductor written by Wentao Zhang and published by Springer Science & Business Media. This book was released on 2012-08-22 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book mainly focuses on the study of the high-temperature superconductor Bi2Sr2CaCu2O8 by vacuum, ultra-violet, laser-based, angle-resolved photoemission spectroscopy (ARPES). A new form of electron coupling has been identified in Bi2212, which occurs in the superconducting state. For the first time, the Bogoliubov quasiparticle dispersion with a clear band back-bending has been observed with two peaks in the momentum distribution curve in the superconducting state at a low temperature. Readers will find useful information about the technique of angle-resolved photoemission and the study of high-temperature superconductors using this technique. Dr. Wentao Zhang received his PhD from the Institute of Physics at the Chinese Academy of Sciences.

Download or read book Angle Resolved Photoemission Spectroscopy on High Temperature Superconductors written by Junfeng He and published by Springer. This book was released on 2016-06-21 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book mainly focuses on the study of the high-temperature superconductor Bi2Sr2CaCu2O8+δ (Bi2212) and single-layer FeSe film grown on SrTiO3 (STO) substrate by means of angle-resolved photoemission spectroscopy (ARPES). It provides the first electronic evidence for the origin of the anomalous high-temperature superconductivity in single-layer FeSe grown on SrTiO3 substrate. Two coexisted sharp-mode couplings have been identified in superconducting Bi2212. The first ARPES study on single-layer FeSe/STO films has provided key insights into the electronic origin of superconductivity in this system. A phase diagram and electronic indication of high Tc and insulator to superconductor crossover have been established in the single-layer FeSe/STO films. Readers will find essential information on the techniques used and interesting physical phenomena observed by ARPES.

Download or read book Angle resolved Photoemission Spectroscopy ARPES Studies of Cuprate Superconductors written by and published by . This book was released on 2010 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is comprised of three different angle-resolved photoemission spectroscopy (ARPES) studies on cuprate superconductors. The first study compares the band structure from two different single layer cuprates Tl2Ba2CuO6+[delta] (Tl2201) Tc, max ~95 K and (Bi1.35Pb0.85)(Sr1.47La0.38)CuO6+[delta] (Bi2201) Tc, max 35 K. The aim of the study was to provide some insight into the reasons why single layer cuprate's maximum transition temperatures are so different. The study found two major di erences in the band structure. First, the Fermi surface segments close to ([pi],0) are more parallel in Tl2201 than in Bi2201. Second, the shadow band usually related to crystal structure is only present in Bi2201, but absent in higher Tc Tl2201. The second study looks at the different ways of doping Bi2Sr2CaCu2O8+[delta] (Bi2212) in-situ by only changing the post bake-out vacuum conditions and temperature. The aim of the study is to systematically look into the generally overlooked experimental conditions that change the doping of a cleaved sample in ultra high vacuum (UHV) experiments. The study found two major experimental facts. First, in inadequate UHV conditions the carrier concentration of Bi2212 increases with time, due to the absorption of oxygen from CO2/CO molecules, prime contaminants present in UHV systems. Second, in a very clean UHV system at elevated temperatures (above about 200 K), the carrier concentration decreases due to the loss of oxygen atoms from the Bi-O layer. The final study probed the particle-hole symmetry of the pseudogap phase in high temperature superconducting cuprates by looking at the thermally excited bands above the Fermi level. The data showed a particle-hole symmetric pseudogap which symmetrically closes away from the nested FS before the node. The data is consistent with a charge density wave (CDW) origin of the pseudogap, similar to STM checkerboard patterns in the pseudogap state.

Download or read book Low Energy Excitations in Cuprate High Temperature Superconductors written by Inna Vishik and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanism of superconductivity in the cuprate high temperature superconductors is an enduring problem in condensed matter physics, and a detailed experimental phenomenology is a crucial starting point for microscopic understanding. Angle-resolved photoemission spectroscopy (ARPES) measures electronic structure in momentum-space. Low-energy excitations in the cuprates, including the superconducting gap, are known to be anisotropic in momentum space, so the momentum resolution afforded by ARPES is key to understanding the physics and uncovering the mechanism. In this dissertation, I present experiments which pursue the cuprate superconductivity problem from several angles: understanding electron-boson coupling which may be involved in mediating superconductivity (Chapters 6 and 7 and Appendix B), understanding the momentum-space structure of the normal state pseudogap (Chapter 5 and Appendix A), understanding how superconductivity coexists with the pseudogap and other phases (Chapters 3 and 4). Much of this work took advantage of a recent development in ARPES technology, using a UV laser as a light source, which allows experiments to be performed with superior energy and momentum resolution. These experiments highlight the wealth of information that is available in ARPES data, including dispersions, scattering rates, and spectral gaps, and they demonstrate the importance of exploring these variables comprehensively as a function of temperature, doping, and momentum.

Download or read book High Temperature Superconductors written by X G Qiu and published by Elsevier. This book was released on 2011-03-28 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: High temperature superconductors have received a great deal of attention in recent years, due to their potential in device and power applications. This book summarises the materials science and physics of all the most important high temperature superconductors as well as discussing material growth, properties and applications.Part one covers fundamental characteristics of high temperature superconductors and high TC films such as deposition technologies, growth, transport properties and optical conductivity. Part two is concerned with growth techniques and properties of high temperature superconductors, including YBCO, BSCCO and HTSC high TC films, and electron-doped cuprates. Finally, part three describes the various applications of high temperature superconductors, from Josephson junctons and dc-superconductive quantum inference devices (dc-SQUIDs) to microwave filters.With its distinguished editor and international team of contributors, this book is an invaluable resource for those researching high temperature superconductors, in industry and academia. In light of the many recent advances in high temperature superconductors, it will benefit physicists, materials scientists and engineers working in this field, as well as in areas of industrial application, such as electronic devices and power transmission. - Summarises the materials science and physics of all the most important high temperature superconductors - Discusses material growth, properties and applications - Outlines fundamental characteristics of high temperature superconductors and high TC films

Download or read book Spin Spirals and Charge Textures in Transition Metal Oxide Heterostructures written by Alex Frano and published by Springer. This book was released on 2014-05-28 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the results of resonant and non-resonant x-ray scattering experiments demonstrating the control of collective ordering phenomena in epitaxial nickel-oxide and copper-oxide based superlattices. Three outstanding results are reported: (1) LaNiO3-LaAlO3 superlattices with fewer than three consecutive NiO2 layers exhibit a novel spiral spin density wave, whereas superlattices with thicker nickel-oxide layer stacks remain paramagnetic. The magnetic transition is thus determined by the dimensionality of the electron system. The polarization plane of the spin density wave can be tuned by epitaxial strain and spatial confinement of the conduction electrons. (2) Further experiments on the same system revealed an unusual structural phase transition controlled by the overall thickness of the superlattices. The transition between uniform and twin-domain states is confined to the nickelate layers and leaves the aluminate layers unaffected. (3) Superlattices based on the high-temperature superconductor YBa2Cu3O7 exhibit an incommensurate charge density wave order that is stabilized by heterointerfaces. These results suggest that interfaces can serve as a powerful tool to manipulate the interplay between spin order, charge order, and superconductivity in cuprates and other transition metal oxides.

Download or read book Uniaxial Pressure Study of Charge Density Waves in a High T Cuprate Superconductor written by Hun-ho Kim and published by Springer Nature. This book was released on 2022-05-07 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents comprehensive studies of charge density waves (CDW) in a high-Tc cuprate superconductor using x-ray scattering techniques under uniaxial pressure. Specifically, the work addresses inelastic x-ray scattering studies under uniaxial pressure performed on the underdoped cuprate YBa2Cu3O6.67(p=0.12, Tc=65K) with incoming photon energy in the resonant (E=931.3 eV, Cu-L3 edge) and non-resonant conditions (E=17.794 keV). This is a completely new approach to the investigation of charge density waves. It revealed new features of charge density waves in cuprates, whose properties had previously been inaccessible..

Download or read book Photoemission Studies of High Temperature Superconductors written by David W. Lynch and published by Cambridge University Press. This book was released on 2005-09-08 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the current status and results of photoelectron spectroscopic techniques, both theoretical and experimental, that have been applied to the study of the cuprate ("high-temperature") superconductors. The techniques described include angle-resolved photoelectron spectroscopy of valence electrons, core level spectra (XPS), and some special variations, such as resonance photoemission. Attention is paid to the difficulties in interpreting such spectra and to the problems obtaining good sample surfaces and high resolution, comparing results from other experimental techniques as well. The authors also outline expected future developments in the techniques. This book will be of great interest to graduate students and researchers in physics, chemistry and materials science with an interest in high temperature superconductors.

Download or read book Spectroscopy of High Tc Superconductors written by N.M. Plakida and published by CRC Press. This book was released on 2003-03-20 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite ten years of intensive research, many questions remain unanswered concerning the nature of the electronic structure (Fermi vs non-Fermi liquid) and mechanisms of superconductivity. Spectroscopy of High-Tc Superconductors, A Theoretical View provides a current, comprehensive review of the experimental results and theoretical interpretations concerning elementary excitation spectra (electronic, phononic, charge, and spin fluctuations) in high-Tc superconductors (HTSC). It discusses accepted microscopic models that describe the electronic structure of the copper-oxide plane - the three-band model, the generalized Emery model, the one-band Hubbard model, different kinds of the t-J model, and the regular Kondo-lattice model - and compares them with ARPES experiments. Leading Russian researchers also consider experimental results obtained by Raman scattering both by phonons and electronic excitations, including magnetic excitations in antiferromagnets in the normal phase, on almost all the types of superconducting cuprates. The results are treated theoretically with the emphasis on features thought to be related to superconductivity. The book also gives an account of the properties of the microwave surface impedance and complex conductivity as functions of temperature common for high-quality single crystals: YBCO, BSCCO, TBCCO, and BKBO. The basics of the muon method and a review of experimental results for superconducting states of different HTSC-compounds are also presented. By offering a thorough examination of current research in the field, this book will appeal to advanced students and researchers working in superconductivity and theoretical condensed matter physics.

Download or read book Physical Properties of High Temperature Superconductors written by Rainer Wesche and published by John Wiley & Sons. This book was released on 2015-05-13 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: A much-needed update on complex high-temperaturesuperconductors, focusing on materials aspects; this timely bookcoincides with a recent major break-through of the discovery ofiron-based superconductors. It provides an overview of materials aspects of high-temperaturesuperconductors, combining introductory aspects, description of newphysics, material aspects, and a description of the materialproperties This title is suitable for researchers inmaterials science, physics and engineering. Also for techniciansinterested in the applications of superconductors, e.g. asbiomagnets

Download or read book Angle Resolved Photoemission Spectroscopy on Electronic Structure and Electron Phonon Coupling in Cuprate Superconductors written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In addition to the record high superconducting transition temperature (T{sub c}), high temperature cuprate superconductors are characterized by their unusual superconducting properties below T{sub c}, and anomalous normal state properties above T{sub c}. In the superconducting state, although it has long been realized that superconductivity still involves Cooper pairs, as in the traditional BCS theory, the experimentally determined d-wave pairing is different from the usual s-wave pairing found in conventional superconductors. The identification of the pairing mechanism in cuprate superconductors remains an outstanding issue. The normal state properties, particularly in the underdoped region, have been found to be at odd with conventional metals which is usually described by Fermi liquid theory; instead, the normal state at optimal doping fits better with the marginal Fermi liquid phenomenology. Most notable is the observation of the pseudogap state in the underdoped region above T{sub c}. As in other strongly correlated electrons systems, these unusual properties stem from the interplay between electronic, magnetic, lattice and orbital degrees of freedom. Understanding the microscopic process involved in these materials and the interaction of electrons with other entities is essential to understand the mechanism of high temperature superconductivity. Since the discovery of high-T{sub c} superconductivity in cuprates, angle-resolved photoemission spectroscopy (ARPES) has provided key experimental insights in revealing the electronic structure of high temperature superconductors. These include, among others, the earliest identification of dispersion and a large Fermi surface, an anisotropic superconducting gap suggestive of a d-wave order parameter, and an observation of the pseudogap in underdoped samples. In the mean time, this technique itself has experienced a dramatic improvement in its energy and momentum resolutions, leading to a series of new discoveries not thought possible only a decade ago. This revolution of the ARPES technique and its scientific impact result from dramatic advances in four essential components: instrumental resolution and efficiency, sample manipulation, high quality samples and well-matched scientific issues. The purpose of this treatise is to go through the prominent results obtained from ARPES on cuprate superconductors. Because there have been a number of recent reviews on the electronic structures of high-T{sub c} materials, we will mainly present the latest results not covered previously, with a special attention given on the electron-phonon interaction in cuprate superconductors. What has emerged is rich information about the anomalous electron-phonon interaction well beyond the traditional views of the subject. It exhibits strong doping, momentum and phonon symmetry dependence, and shows complex interplay with the strong electron-electron interaction in these materials. ARPES experiments have been instrumental in identifying the electronic structure, observing and detailing the electron-phonon mode coupling behavior, and mapping the doping evolution of the high-T{sub c} cuprates. The spectra evolve from the strongly coupled, polaronic spectra seen in underdoped cuprates to the Migdal-Eliashberg like spectra seen in the optimally and overdoped cuprates. In addition to the marked doping dependence, the cuprates exhibit pronounced anisotropy with direction in the Brillouin zone: sharp quasiparticles along the nodal direction that broaden significantly in the anti-nodal region of the underdoped cuprates, an anisotropic electron-phonon coupling vertex for particular modes identified in the optimal and overdoped compounds, and preferential scattering across the two parallel pieces of Fermi surface in the antinodal region for all doping levels. This also contributes to the pseudogap effect. To the extent that the Migdal-Eliashberg picture applies, the spectra of the cuprates bear resemblance to that seen in established strongly coupled electron-phonon superconductors such as Pb. On the other hand, the cuprates deviate from this conventional picture. In the underdoped regime, the carriers are best understood as small polarons in an antiferromagnetic, highly electron correlated background, while the doped compounds require an anisotropic electron-phonon vertex to detail the prominent mode coupling signatures in the superconducting state. Electronic vertex corrections to the electron-phonon coupling furthermore may enhance, and for certain phonons, determine, the anisotropy of the electron-phonon coupling. A consistent picture emerges of the cuprates, combining strong, anisotropic electron-phonon coupling, particular phonon modes that could give rise to such a coupling, and an electron-electron interaction modifying the el-ph vertex.

Download or read book Study of High Temperature Superconductors with Angle resolved Photoemission Spectroscopy written by Pavel Valere̓vich Bogdanov and published by . This book was released on 2002 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Very High Resolution Photoelectron Spectroscopy written by Stephan Hüfner and published by Springer Science & Business Media. This book was released on 2007-02-09 with total page 411 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photoemission spectroscopy is one of the most extensively used methods to study the electronic structure of atoms, molecules, and solids and their surfaces. This volume introduces and surveys the field at highest energy and momentum resolutions allowing for a new range of applications, in particular for studies of high temperature superconductors.

Download or read book 100 Years of Superconductivity written by Horst Rogalla and published by Taylor & Francis. This book was released on 2011-11-11 with total page 866 pages. Available in PDF, EPUB and Kindle. Book excerpt: Even a hundred years after its discovery, superconductivity continues to bring us new surprises, from superconducting magnets used in MRI to quantum detectors in electronics. 100 Years of Superconductivity presents a comprehensive collection of topics on nearly all the subdisciplines of superconductivity. Tracing the historical developments in supe

Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Challenges in Superconductivity Experimental Advances and Emerging Theories written by J. Ashkenazi and published by Springer Science & Business Media. This book was released on 2006-01-24 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the 2004 University of Miami Workshop on Unconventional Superconductivity. The workshop was the fourth in a series of successful meetings on High-T Superconductivity and C related topics, which took place at the James L. Knight Physics Building on the University of Miami campus in Coral Gables, Florida, in January 1991, 1995, 1999, and 2004. The workshop consisted of two consecutive events: 1. NATO Advanced Research Workshop (ARW) on New Challenges in Superconductivity: Experimental Advances and Emerging Theories, held on January 11-14, 2004; 2. Symposium on Emerging Mechanisms for High Temperature Superconductivity (SEMHTS), held on January 15-16, 2004. It is hard to write a balanced preface to a volume like this one, yet at least we try to offer the reader a taste of what was happening in this workshop. There were close to a hundred scientists from around the world, albeit fewer Russians than we had originally hoped for. Nevertheless, the workshop was very lively and we trust that this is demonstrated in this volume. The workshop included high-quality presentations on state of the art works, yet a key issue, discussed by many, was how homogeneous the cuprates are. STM data, as well as other reports, showed that the cuprate superconductors (SC’s) studied were inhomogeneous, especially in the underdoped regime; while experiments, like ARPES and magnetoresistance have established the existence of a Fermi Surface (FS), at least above some doping level, in the cuprates.