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 Uniaxial Pressure Study of Charge Density Waves in a High Tc Cuprate Superconductor written by Hun-ho Kim and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Nature of Charge Density Waves Superconductivity and Their Interplay in 1T TiSe2 written by Chuan Chen and published by Springer Nature. This book was released on 2019-09-27 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents analytical theoretical studies on the interplay between charge density waves (CDW) and superconductivity (SC) in the actively studied transition-metal dichalcogenide 1T-TiSe2. It begins by reapproaching a years-long debate over the nature of the phase transition to the commensurate CDW (CCDW) state and the role played by the intrinsic tendency towards excitonic condensation in this system. A Ginzburg-Landau phenomenological theory was subsequently developed to understand the experimentally observed transition from commensurate to incommensurate CDW (ICDW) order with doping or pressure, and the emergence of a superconducting dome that coexists with ICDW. Finally, to characterize microscopically the effects of the interplay between CDW and SC, the spectrum of CDW fluctuations beyond mean-field was studied in detail. In the aggregate, the work reported here provides an encompassing understanding of what are possibly key microscopic underpinnings of the CDW and SC physics in TiSe2.
Download or read book Phononic and Electronic Excitations in Complex Oxides Studied with Advanced Infrared and Raman Spectroscopy Techniques written by Fryderyk Lyzwa and published by Springer Nature. This book was released on 2022-10-05 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This PhD thesis reports on investigations of several oxide-based materials using advanced infrared and Raman spectroscopy techniques and in combination with external stimuli such as high magnetic or electric field, sptial confinement in thin film heterostructures and the radiation with UV light. This leads to new results in the fields of superconductivity, electronic polarization states and nanoscale phenomena. Among these, the observation of anomalous polar moments is of great relevance for understanding the electric-field-induced metal-to-insulator transistion; and the demonstration that confocal Raman spectroscopy of backfolded acoustic photons in metal-oxide multilayers can be used as a powerful characterization tool for monitoring their interface properties and layer thickness is an important technical development for the engineering of such functional oxide heterostructures.
Download or read book Controlling Collective Electronic States in Cuprates and Nickelates written by Martin Bluschke and published by Springer Nature. This book was released on 2020-07-27 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis chemical and epitaxial degrees of freedom are used to manipulate charge and spin ordering phenomena in two families of transition metal oxides, while taking advantage of state-of-the-art resonant x-ray scattering (RXS) methods to characterize their microscopic origin in a comprehensive manner. First, the relationship of charge density wave order to both magnetism and the "pseudogap" phenomenon is systematically examined as a function of charge-carrier doping and isovalent chemical substitution in single crystals of a copper oxide high-temperature superconductor. Then, in copper oxide thin films, an unusual three-dimensionally long-range-ordered charge density wave state is discovered, which persists to much higher temperatures than charge-ordered states in other high-temperature superconductors. By combining crystallographic and spectroscopic measurements, the origin of this phenomenon is traced to the epitaxial relationship with the underlying substrate. This discovery opens new perspectives for the investigation of charge order and its influence on the electronic properties of the cuprates. In a separate set of RXS experiments on superlattices with alternating nickel and dysprosium oxides, several temperature- and magnetic-field-induced magnetic phase transitions are discovered. These observations are explained in a model based on transfer of magnetic order and magneto-crystalline anisotropy between the Ni and Dy subsystems, thus establishing a novel model system for the interplay between transition-metal and rare-earth magnetism.
Download or read book Charge Density Wave Order in Cuprate Superconductors Studied by Resonant Soft X ray Scattering written by Andrew Achkar and published by . This book was released on 2015 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cuprate high temperature superconductors have been the subject of intense investigation since their discovery in 1986. The nature of the pairing mechanism in these unconventional superconductors does not seem to be mediated by phonons, as in conventional superconductors, and thus remains a puzzle. The superconducting phase emerges from doping holes (or electrons) into the copper oxide planes of an anti-ferromagnetic Mott insulator, producing a wealth of electronic ordering phenomena in many of the cuprate families. One of these phases is an incommensurate charge ordered state, known since the mid 90's to occur in La-based cuprates along with incommensurate spin ordering and compete with superconductivity. Recent advances in experimental capabilities, notably the ability to perform resonant diffraction experiments with soft x-rays, which can be made sensitive to holes in Cu 3d and O 2p orbitals, have provided new opportunities to learn about these charge ordered states. The study of charge order in cuprate superconductors by resonant soft x-ray scattering is the subject of this thesis.
Download or read book Studies of Charge Density Waves in Cuprate Superconductors written by Maud C. Barthélemy and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Nature of Charge Density Waves Superconductivity and Their Interplay in 1T TiSe2 written by Chuan Chen and published by . This book was released on 2019 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents analytical theoretical studies on the interplay between charge density waves (CDW) and superconductivity (SC) in the actively studied transition-metal dichalcogenide 1T-TiSe2. It begins by reapproaching a years-long debate over the nature of the phase transition to the commensurate CDW (CCDW) state and the role played by the intrinsic tendency towards excitonic condensation in this system. A Ginzburg-Landau phenomenological theory was subsequently developed to understand the experimentally observed transition from commensurate to incommensurate CDW (ICDW) order with doping or pressure, and the emergence of a superconducting dome that coexists with ICDW. Finally, to characterize microscopically the effects of the interplay between CDW and SC, the spectrum of CDW fluctuations beyond mean-field was studied in detail. In the aggregate, the work reported here provides an encompassing understanding of what are possibly key microscopic underpinnings of the CDW and SC physics in TiSe2.
Download or read book Density Waves In Solids written by George Gruner and published by CRC Press. This book was released on 2018-03-08 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: ?Density Waves in Solids is written for graduate students and scientists interested in solid-state sciences. It discusses the theoretical and experimental state of affairs of two novel types of broken symmetry ground states of metals, charge, and spin density waves. These states arise as the consequence of electron-phonon and electron-electron interactions in low-dimensional metals.Some fundamental aspects of the one-dimensional electron gas, and of the materials with anisotropic properties, are discussed first. This is followed by the mean field theory of the phases transitions?discussed using second quantized formalism?together with the various experimental observations on the transition and on the ground states. Fluctuation effects and the collective excitations are reviewed next, using the Ginzburg-Landau formalism, followed by the review of the interaction of these states with the underlying lattice and with impurities. The final chapters are devoted to the response of the ground states to external perturbations.
Download or read book Charge Density Waves and Electronic Nematicity in the Three Band Model of Cuprate Superconductors written by and published by . This book was released on 2014 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cuprate superconductors exhibit very high critical temperatures, $T_c$, compared to those in the conventional superconductors. The doping at which $T_c$ is maximized is called optimal doping. Below this level, in the underdoped region, cuprate superconductors exhibit not only high $T_c$ superconductivity, but also the celebrated pseudogap phase, a theory of which is still not established. In the pseudogap region cuprates exhibit incommensurate charge orders and electronic nematicity, which are the focus of this thesis. Borrowed from the liquid crystal terminology, nematicity refers to the breaking of rotational symmetry in the electron degree of freedom where charge densities are re-arranged within the unit cell. The aim of this thesis is to establish the microscopic origin of charge orders in cuprates, and provide an explanation for some of the anomalous properties in the pseudogap region. Established by experiments, electronic nematicity originates from the inequivalency of the two oxygen orbitals in the cuprate unit-cell. Using this hint, the instability towards nematic charge orders was studied in the three-band model of cuprate superconductors, which explicitly takes into account the oxygen orbitals. Using the generalized random phase approximation, the nematic charge susceptibility was calculated, and it was found that the three-band model has nematic instabilities driven by the Coulomb repulsion between densities at oxygen orbitals. In the experimentally relevant doping range, the leading charge instability occurs as electronic nematicity with a modulation in space whose periodicity incommensurate with the underlying lattice. Such density modulations cause Fermi surface reconstructions, giving so-called Fermi arcs and small Fermi surface pockets. These findings, as well as the doping dependence of the modulation wavevector, are consistent with experiments. There is some disagreement with experiments as well: the modulation wavevector points along the diagonal of the Brillouin zone as opposed to the zone axes, and its magnitude is about half of that measured experimentally. Further improvement to the model is necessary to better match the experimental findings. A thorough understanding of electronic nematicity and its interplay with other phases is necessary to establish the theory of the pseudogap phase as well as that of the cuprate high-temperature superconductivity.
Download or read book Experimental Studies of High Tc Cuprate Superconductors with Density Wave Correlations written by He Ruihua and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High-Tc cuprate superconductors remain the source of central intellectual challenges for condensed matter physicists two decades after their discovery. Accumulating evidence suggests possible ubiquity of coexisting superconducting and density wave correlations in the ground state of these materials. As both correlations in their spatiotemporally incoherent forms can in principle produce a pseudogap in the excitation spectrum, the nature of the pseudogap widely seen in cuprates above Tc comes to forefront of debate. I have been trying to address the relationship triangle between the pseudogap, superconductivity and density waves, by mainly using angle-resolved photoemission spectroscopy (ARPES) to study the momentum spaces of single-layer La-based (La214) and Bi-based (Bi2201) cuprates. In this thesis, I first talk about our ARPES-neutron scattering joint effort (in collaboration with Tohoku University) in the stripe-ordered state of La214. We found around the 1/8 doping level a dual nature of the pseudogap (in LBCO) and a dual nature of the spin stripe ordering ground state. The latter will be discussed in the context of a doping-dependent crossover between localized- and itinerant-spin ground-state physics, as demonstrated for the first time in a condensed matter system (1% Fe-doped LSCO). I then focus on our ARPES findings in both the pseudogap and superconducting states of nearly optimally-doped Pb-Bi2201 obtained over unprecedented momentum, energy and temperature ranges. They suggest that the pseudogap is a broken-symmetry state that is density-wave like and distinct from homogeneous superconductivity; it explicitly coexists with coherent superconductivity below Tc, causing a striking, momentum-dependent distortion of the high-Tc ground state. I also include in the appendix our recent observation of symmetry-distinct states (likely derived from the Cu dz orbital) in proximity to the Zhang-Rice singlet that has so far been generally taken as the only relevant electronic building block for cuprates. This finding might profoundly transform our upper-level understanding of high-Tc superconductivity as discussed above. This thesis ends with a chapter which describes my experimental philosophy, speculations and outlook for the near future of this field.
Download or read book Recent Trends in Thermoelectric Materials Research Part Two written by and published by Academic Press. This book was released on 2000-10-25 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The Willardson and Beer series, as it is widely known, has succeeded in producing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise that this tradition will be maintained and even expanded.Thermoelectric materials may be used for solid state refrigeration or power generation applications via the large Peltier effect in these materials. To be an effective thermoelectric material, a material must possess a large Seebeck coefficient, a low resistivity and a low thermal conductivity. Due to increased need for alternative energy sources providing environmentally friendly refrigeration and power generation, thermoelectric materials research experienced a rebirth in the mid 1990's. Semiconductors and Semimetals, Volume 70: Recent Trends in Thermoelectric Materials Research: Part Two provides an overview of much of this research in thermoelectric materials during the decade of the 1990's. New materials and new material concepts such as quantum well and superlattice structures gave hope to the possibilities that might be achieved. An effort was made to focus on these new materials and not on materials such as BiTe alloys, since such recent reviews are available. Experts in the field who were active researchers during this period were the primary authors to this series of review articles. This is the most complete collection of review articles that are primarily focussed on new materials and new concepts that is existence to date.
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1058 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Conductor Insulator Quantum Phase Transitions written by Vladimir Dobrosavljevic and published by Oxford University Press. This book was released on 2012-06 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Studies in the D density Wave State in Relation to the High Tc Cuprate Superconductors written by Sumanta Tewari and published by . This book was released on 2003 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Charge Density Waves and Phonon Excitations of Superconducting Cuprate La1 6 xNd0 4 SrxCuO4 Revealed by Resonant Soft X ray Scattering written by Jung-Han Li and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Engineering Index Annual written by and published by . This book was released on 1992 with total page 2264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its creation in 1884, Engineering Index has covered virtually every major engineering innovation from around the world. It serves as the historical record of virtually every major engineering innovation of the 20th century. Recent content is a vital resource for current awareness, new production information, technological forecasting and competitive intelligence. The world?s most comprehensive interdisciplinary engineering database, Engineering Index contains over 10.7 million records. Each year, over 500,000 new abstracts are added from over 5,000 scholarly journals, trade magazines, and conference proceedings. Coverage spans over 175 engineering disciplines from over 80 countries. Updated weekly.
