84 research outputs found
Flux lattice melting in the high Tc superconductors
One of the important issues for technological application of the high temperature superconductors is their behavior in a magnetic field. A variety of experiments including electrical transport, mechanical oscillators, and magnetic decoration have suggested that these magnetic properties will make applications more difficult than originally anticipated. These experiments and their results are briefly discussed
ARPES Line Shapes in FL and non-FL Quasi-Low-Dimensional Inorganic Metals
Quasi-low-dimensional (quasi-low-D) inorganic materials are not only ideally
suited for angle resolved photoemission spectroscopy (ARPES) but also they
offer a rich ground for studying key concepts for the emerging paradigm of
non-Fermi liquid (non-FL) physics. In this article, we discuss the ARPES
technique applied to three quasi-low-D inorganic metals: a paradigm Fermi
liquid (FL) material TiTe, a well-known quasi-1D charge density wave
(CDW) material KMoO and a quasi-1D non-CDW material
LiMoO. With TiTe, we establish that a many body
theoretical interpretation of the ARPES line shape is possible. We also address
the fundamental question of how to accurately determine the {\bf k} value
from ARPES. Both KMoO and LiMoO show
quasi-1D electronic structures with non-FL line shapes. A CDW gap opening is
observed for KMoO, whereas no gap is observed for
LiMoO. We show, however, that the standard CDW theory,
even with strong fluctuations, is not sufficient to describe the non-FL line
shapes of KMoO. We argue that a Luttinger liquid (LL) model is
relevant for both bronzes, but also point out difficulties encountered in
comparing data with theory. We interpret this situation to mean that a more
complete and realistic theory is necessary to understand these data.Comment: 23 pages, including 21 figures; to appear in a special issue of J.
Elec. Spectr. Rel. Pheno
Fermi surfaces and single-particle spectral functions of low-dimensional inorganic non-cuprate compounds: the molybdenum bronzes
The Fermi surfaces and single-particle spectral functions of several low-dimensional materials have been measured as part of an effort to assess the occurrence of non-Fermi-liquid behaviour in non-cuprate materials.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48877/2/c64816.pd
Superconductivity-induced Resonance Raman Scattering in Multi-layer High-Tc Superconductors
Resonant Raman scattering below Tc has been discovered in several Bi-, Hg-,
Tl-based high-Tc superconductors with three or four CuO2-layers. For
Bi2Si2Ca2Cu3O10+d, we found an unexpected crossover of the pair-breaking peak
in the A1g-spectrum from a broad bump at hw = 6kBTc for Eexc = 2.54eV to a
sharp peak at hw = 8kBTc for Eexc = 2.18eV, together with a strong enhancement
of the Ca-phonons. Under resonant conditions, the relative positions of the
pair breaking peaks in A1g, B1g, and B2g channels are 2Delta(A1g) = 2Delta(B1g)
> 2Delta(B2g). This relation implies that the A1g Raman channel is free from
the Coulomb screening effect, just as predicted theoretically for a d-wave
multi-layer superconductor but have never been observed experimentally thus
far. The observed resonance effect is the evidence that the electronic state in
the inner CuO2-planes is different from that of the outer CuO2-planes.Comment: 16 pages, 6 figures. submitted to Phys.Rev.
Electron correlations on a mesoscopic scale: Magnetic properties of transition metal telluride cluster compounds
Preparation of Vanadium‐Tungsten‐Oxide Wadsley‐Roth Phases by Electrolytic Reduction of Molten Salts
- …