Download or read book High Energy Resolution Angle resolved Photoemission Studies of Electronic Properties of Bi based High Temperature Superconductors written by Jian Ma and published by . This book was released on 1995 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 High Resolution angle Resolved Photoemission Studies of High Temperature Superconductors written by and published by . This book was released on 1989 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent photoemission studies of Y 123 and Bi 2212 performed with high energy and angular resolution have provided detailed information on the nature of the states near the Fermi level. Measurements of the superconducting gap, band dispersion, and the density of states near the Fermi level in the normal state all support a Fermi liquid description of these materials. 5 refs., 4 figs.
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 1999-05-28 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes important topics in high-temperature superconductivity; for graduate students and researchers.
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 High Resolution Photoemission Studies of Interfaces in High Tc Superconductors written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our research has involved using angle-resolved photoemission spectroscopy (ARPES) as a nano-scale probe of the electronic structure of surfaces and interfaces of high-temperature superconductors. Photoemission has provided unique and valuable information because of its surface sensitivity, excellent energy resolution, and ability to detect core-level chemical shifts. The information has strong implications for a fundamental understanding of the electronic structure of the cuprates as well as the construction of practical devices such as Josephson junctions. We will focus on: (1) description of custom-designed thin film samples of high temperature superconductors (HTSC) and the development of methods to study them with ARPES, (2) electronic structure measurements using ARPES, including the measurement of energy gaps, (3) the implications for characteristics of devices using HTSC, and (4) proximity effect searches.
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 High Resolution Angle resolved Photoemission Study of Hightemperature Superconductors written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The latest development of angle-resolved photoemission spectroscopy (ARPES) technique has seen extremely high energy resolution and momentum resolution, as well as multiple angle detection. These advancements have led to new findings through efficient Fermi surface mapping, fine electronic structure resolving, and direct determination of electron self-energy. In this paper, we will highlight some recent high resolution ARPES work on high temperature superconductors. These include: (1) charge-ordering and evolution of electronic structure with doping; (2) bilayer splitting and Fermi surface topology of Bi2212; and (3) strong electron phonon coupling and electron electron interaction in high temperature superconductors.
Download or read book High resolution Photoemission Study of the High Temperature Superconductors written by Yeukuang Hwu and published by . This book was released on 1992 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of High Temperature Superconductors with Angle Resolved Photoemission Spectroscopy written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Angle Resolved Photoemission Spectroscopy (ARPES) recently emerged as a powerful tool for the study of highly correlated materials. This thesis describes the new generation of ARPES experiment, based on the third generation synchrotron radiation source and utilizing very high resolution electron energy and momentum analyzer. This new setup is used to study the physics of high temperature superconductors. New results on the Fermi surfaces, dispersions, scattering rate and superconducting gap in high temperature superconductors are presented.
Download or read book High resolution Angle resolved Photoemission Studies of High Tc Superconductor Bi Sub 2 Sr Sub 2 CaCu Sub 2 O Sub 8 written by and published by . This book was released on 1990 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: An angle-resolved photoemission study of the normal and superconducting states in Bi2Sr2CaCu2O was performed. Measurements in the normal state show bands dispersing through the Fermi level from at least 350 meV below E{sub F}. The Fermi level crossings are consistant with local-density band calculation, including a point calculated to be of Bi-O character. Additional measurements were made where bands crossed the Fermi level between 100 and 250K, along with measurements on an adjacent Pt foil. The Fermi edges of both materials agree to within the noise. Below the Fermi level, the spectra show correlation effects on the form of an increased effective mass. The shape of the spectra can be explained by a lifetime-broadened photohole and secondary electrons. The effective inverse photohole lifetime is linear in energy. A superconducting gap has been measured at a number of points where there is density at the Fermi level in the normal state. By proper modeling, a gap of 24 meV was obtained for all these points, including points of Cu-O and Bi-O character respectively, according to band calculation. The lack of gap anisotropy in the basal plane suggests that pinning in this material is not d-wave pairing.
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 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 Energy Research Abstracts written by and published by . This book was released on 1993 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photoemission Studies of High Tc Superconductors written by Daniel S. Dessau and published by . This book was released on 1992 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Temperature Cuprate Superconductors written by Nikolay Plakida and published by Springer Science & Business Media. This book was released on 2010-08-26 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-Temperature Cuprate Superconductors provides an up-to-date and comprehensive review of the properties of these fascinating materials. The essential properties of high-temperature cuprate superconductors are reviewed on the background of their theoretical interpretation. The experimental results for structural, magnetic, thermal, electric, optical and lattice properties of various cuprate superconductors are presented with respect to relevant theoretical models. A critical comparison of various theoretical models involving strong electron correlations, antiferromagnetic spin fluctuations, phonons and excitons provides a background for understanding of the mechanism of high-temperature superconductivity. Recent achievements in their applications are also reviewed. A large number of illustrations and tables gives valuable information for specialists. A text-book level presentation with formulation of a general theory of strong-coupling superconductivity will help students and researches to consolidate their knowledge of this remarkable class of materials.
