Download or read book Scanning Tunneling Spectroscopy of Bi Based High Temperature Superconductors written by Craig Martin Howald and published by . This book was released on 2002 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book In plane Tunneling Spectroscopy of the High Temperature Superconductor Bi 2212 written by Jeffrey William Kane and published by . This book was released on 1997 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bismuth Based High Temperature Superconductors written by Hiroshi Maeda and published by CRC Press. This book was released on 1996-07-09 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides coverage of the ongoing investigations on bismuth-based high-temperature cuprate superconductors, integrating scattered research activities and literature from 70 leading scientists throughout the world. The text covers crystal structures and microstructures, reversible or equilibrium magnetic and thermal properties, atomic site tunnel spe

Download or read book Bismuth Based High Temperature Superconductors written by Hiroshi Maeda and published by CRC Press. This book was released on 1996-07-09 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides coverage of the ongoing investigations on bismuth-based high-temperature cuprate superconductors, integrating scattered research activities and literature from 70 leading scientists throughout the world. The text covers crystal structures and microstructures, reversible or equilibrium magnetic and thermal properties, atomic site tunnel spectroscopy, experimental studies concerning equilibrium phases, and more.

Download or read book Scanning Tunneling Spectroscopy of Topological Insulators and Cuprate Superconductors written by Michael Manchun Yee and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past twenty-five years, condensed matter physics has been developing materials with novel electronic characteristics for a wide range of future applications. Two research directions have shown particular promise: topological insulators, and high temperature copper based superconductors (cuprates). Topological insulators are a newly discovered class of materials that can be manipulated for spintronic or quantum computing devices. However there is a poor spectroscopic understanding of the current topological insulators and emerging topological insulator candidates. In cuprate superconductors, the challenge lies in raising the superconducting transition temperature to temperatures accessible in non-laboratory settings. This effort has been hampered by a poor understanding of the superconducting mechanism and its relationship with a mysterious pseudogap phase. In this thesis, I will describe experiments conducted on topological insulators and cuprate superconductors using scanning tunneling microscopy and spectroscopy, which provide nanoscale spectroscopic information in these materials.

Download or read book Elastic and Inelastic Scanning Tunneling Spectroscopy on Iron Based Superconductors written by Jandke, Jasmin Maria and published by KIT Scientific Publishing. This book was released on 2019-05-02 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scanning Tunneling Spectroscopy of Anisotropic High Temperature Superconductors written by Amos Sharoni and published by . This book was released on 2004 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Scanning Tunneling Microspectroscopy of Solids and Surfaces Final Report written by and published by . This book was released on 2002 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental and theoretical research on the bulk and surface properties of conductive solid state materials has been performed based on the techniques of scanning tunneling microscopy and scanning tunneling spectroscopy, often at cryogenic temperatures. The research has focused on the electronic properties, particularly the superconductivity, of high temperature superconductors and other layered systems. The superconducting electronic density of states N(E)=dI/dV of the high T{sub c} superconductor Bi2Sr2CaCu2O{sub 8+{delta}} was measured with spatial resolution of 5 A at 4.2K. An internal superconducting proximity effect was inferred to operate between Cu and Bi based layers of the crystal in those regions where the Bi layers are metallic in nature. This research project supported the thesis research of several young scientists, and led to a significant number of published papers, presentations and reports.

Download or read book Schackert Michael PeterScanning Tunneling Spectroscopy on Electron Boson Interactions in Superconductors written by Schackert, Michael Peter and published by KIT Scientific Publishing. This book was released on 2015-03-23 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work describes the experimental study of electron-boson interactions in superconductors by means of inelastic electron tunneling spectroscopy performed with a scanning tunneling microscope (STM) at temperatures below 1 K. This new approach allows the direct measurement of the Eliashberg function of conventional superconductors as demonstrated on lead (Pb) and niobium (Nb). Preparative experiments on unconventional iron-pnictides are presented in the end.

Download or read book Scanning Tunneling Spectroscopy Studies of High temperature Cuprate Superconductors written by Ching-Tzu Chen and published by . This book was released on 2006 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: A much-needed update on complex high-temperature superconductors, focusing on materials aspects; this timely book coincides with a recent major break-through of the discovery of iron-based superconductors. It provides an overview of materials aspects of high-temperature superconductors, combining introductory aspects, description of new physics, material aspects, and a description of the material properties This title is suitable for researchers in materials science, physics and engineering. Also for technicians interested in the applications of superconductors, e.g. as biomagnets

Download or read book Scanning Tunneling Spectroscopy Study of Inhomogeneity Granularity Segregation in the Electronic Structure of Bi2Sr2CaCu2O delta written by Kristine Michelle Lang and published by . This book was released on 2001 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tunneling Spectroscopy in Thallium Based High Temperature Superconductors written by Stephan Friedrich and published by . This book was released on 1991 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Imaging the Two Gaps of the High Temperature Superconductor Pb Bi2Sr2CuO6 x written by Ming Yi (S.M.) and published by . This book was released on 2007 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nature and behavior of electronic states in high temperature superconductors are the center of much debate. The pseudogap state, observed above the superconducting transition temperature Tc, is seen by some as a precursor to the superconducting state. Others view it as a competing phase. Recently, this discussion has focused on the number of energy gaps in the system. Some experiments indicate a single energy gap, implying that the pseudogap is a precursor state. Others indicate two, suggesting that it is a competing or coexisting phase. In this thesis, I report temperature dependent scanning tunneling spectroscopy of Pb-Bi2Sr2 CuO6+6 . I have developed a novel analytical method that reveals a new, narrow, homogeneous gap that vanishes near Tc, superimposed on the typically observed, inhomogeneous, broad gap, which is only weakly temperature dependent. These results not only support the two gap picture, but also explain previously troubling differences between scanning tunneling microscopy and other experimental measurements.

Download or read book Tunneling Spectroscopy Studies of Superconductors written by Basu Dev Oli and published by . This book was released on 2021 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: In multiband superconductors, different bands at the Fermi surface contribute to the superconductivity with different magnitudes of superconducting gaps on different portions of the Fermi surface. Each band in a multiband superconductor has a condensate with an amplitude and phase that weakly interacts with the other bands' condensate. The coupling strength between the bands determines whether one or two superconducting transition temperatures are observed, and it is the key to many peculiar properties. In general, if there are two gaps of different magnitude, there are two different length scales associated with the suppression of these gaps in applied magnetic fields, for example. Therefore, effects of multigap superconductivity can be observed in superconducting vortices, which are twirls of supercurrents that are generated when a superconductor is placed in a magnetic field. Furthermore, the two superconducting order parameters in different bands are characterized by a magnitude and phase. In multiband superconductors, there are collective excitations corresponding to fluctuations of the relative phase of two order parameters, so-called the Leggett mode. The first material identified as multiband superconductor is Magnesium Diboride (MgB2) in 2001 with a critical temperature Tc of 39 K. MgB2 is a superconducting material with the highest transition temperature among all conventional BCS superconductors. It has two superconducting gaps \Delta_\pi ~ 2 meV and \Delta_\sigma\ ~ 7 meV and they arise from the existence of two bands \pi and \sigma bands of boron electrons. The discovery of superconductivity in MgB2 renewed interest in the field of multiband superconductivity. MgB2 has attracted many scientists' attention both for the fundamental importance of understanding the multiband superconductivity and possible applications such as magnets, power cables, bolometers, Josephson junction-based electronic devices, and radio-frequency cavities. Afterward, other materials have been identified as multiband superconductors such as NbSe2, the family of iron-based superconductors, heavy fermion superconductors, multilayer cuprates, borocarbides, etc. This dissertation uses tunneling experiments to highlight multiband superconductivity features in two systems, namely MgB2 thin films and ultrathin films of Pb. Further, we use multiple techniques to study a superconducting material, nitrogen-doped niobium, used for superconducting radio-frequency cavities. For the project on MgB2, MgB2/Native-Oxide/Ag planar junctions are fabricated and characterized down to 2.1 K and in the magnetic field parallel to the sample surface up to 6 Tesla. This work investigates how pairbreaking affects the magnitude and phase of the order parameter in a multiband superconductor. The tunneling spectra are analyzed in the framework of a two-band model developed by our theory collaborator Prof. Alex Gurevich, Old Dominion University. The model allows the extraction of the pair-breaking parameters among other quantities. The analysis shows that the order parameter in the ? band is quickly suppressed in the field, the ? band is cleaner than the ? band. The ratio of pairbreaking parameter in the ? band to the ? band rapidly increases at fields higher than ~0.1 T and then plateau at higher fields. This transition around 0.1 T magnetic field suggests a phase decoupling in the two bands of MgB2. Below the transition, the two bands are phase-locked, so mostly, the superconductivity in the ? band is affected, and after phase decoupling, both bands are affected by the applied field. These results are important for a basic understanding of multiband superconductors and the application implications of this material. This phase decoupling has a new and profound consequence on the superconducting state of a multiband superconductor that has been theoretically predicted and never observed experimentally. For the Pb project, ultrathin films of Pb in ultrahigh vacuum conditions are deposited by e-beam evaporation and characterized with low-temperature scanning tunneling microscopy and spectroscopy (STM/STS). The STM/STS allows measuring the electronic density of states with the highest spatial resolution down to atomic scale. The shape of a superconducting vortex core is determined by the superconducting gap and the Fermi velocity, and the STM allows to map anisotropies of these quantities spatially. The vortex cores of Pb film show a complex shape that evolves from triangular at short distances from the center to a six-fold symmetric star shape farther away from the center. These details are very subtle, and they can be highlighted only if one works within the clean limit (to avoid the averaging effect of the scattering) and by fabricating the heterostructure that pins the vortices spatially. The complex vortex core shape reflects the anisotropy of the two bands that contribute to superconductivity in this material. For the project on Niobium, cold and hot spots from nitrogen-doped Nb cutouts are characterized by low temperature scanning tunneling microscopy and spectroscopy (STM/STS) combined with X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The radiofrequency (RF) measurements of the quality factor and temperature mapping on an N-doped Nb superconducting resonator cavity are carried out at Jefferson Laboratory before cutting out the samples. This work aims to identify possible sources of excess dissipation in hot spots and relate them to the surface chemical composition and superconducting properties. The temperature mapping revealed a strong effect of the cavity cooldown rate on the intensities of hot spots and their spatial distribution, which indicates a significant contribution of trapped vortices to the RF dissipation. SEM images acquired on the cold and hot spots using a secondary electron detector show absence of residual hydride scars and niobium nitrides on their surface. Angle-resolved XPS measurements on the native surface of these samples revealed higher oxidized Nb 3d states on the N-doped Nb cold spots, which is supported by XPS depth profiles done on the samples by Argon ion sputtering. Argon ion sputtering of oxidized Nb removes oxygen preferentially from Nb2O5 and diffuses to bulk, thickening the lower oxidation state layers. The proximity theory framework's tunneling spectra analysis suggests hot spots have stronger pairbreaking due to a weakly reduced pair potential, a thicker metallic suboxide layer, and a wide distribution of the contact resistance. STM imaging of vortex cores shows a triangular vortex lattice in both samples, and the coherence length is nearly the same in hot and cold spots. The experimental data analysis suggests weakly degraded superconducting properties at the surface of hot spot regions are not the primary sources of RF losses. Instead, they are the regions where vortices nucleate first and get trapped during cooling down. These experimental techniques and findings will be crucial in helping to qualify new recipes for SRF cavity production and to boost their performance.

Download or read book A Search for Alternative Electronic Order in the High Temperature Superconductor Bi2Sr2CaCu2O8 delta by Scanning Tunneling Microscopy written by Jennifer Eve Hoffman and published by . This book was released on 2003 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: