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Itinerant Electrons (itinerant + electron)

Distribution by Scientific Domains

Physics and Astronomy	50%
Chemistry	50%

Selected Abstracts

Can the Fulleride superconducting model (FSM) be extended?

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 5 2005
R. H. Squire
Abstract The Fulleride superconducting model (FSM) is based on the existence of an electron (or Cooper) pair density wave localized on a single Fulleride molecule. Interaction of the wave with itinerant electrons at low temperature creates a pseudo-gap above the superconducting state. In addition, the interaction of the electron and the bosonic pair create a net attraction between two Fulleride molecules resulting in an intermolecular Cooper pair. This pairing interaction appears to have all the aspects of a spin liquid. This study extends the model to high-temperature superconductors and suggests that superconductivity may exist with considerably fewer molecules than in BCS theory. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [source]

MVPACK: A package to calculate energy levels and magnetic properties of high nuclearity mixed valence clusters,

JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 6 2010
J. J. Borrás-Almenar
Abstract We present a FORTRAN code based on a new powerful and efficient computational approach to solve the double exchange problem for high-nuclearity MV clusters containing arbitrary number of localized spins and itinerant electrons. We also report some examples in order to show the possibilities of the program. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 [source]

SWNT probed by multi-frequency EPR and nonresonant microwave absorption

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2008
B. Corzilius
Abstract In addition to g = 2.00 signals seen frequently in EPR spectra of SWNT, signals at g = 2.07 of SWNT prepared by CVD were detected, exhibiting a Pauli susceptibility temperature dependence. This Pauli magnetism in combination with the large g shift is taken as evidence that these signals originate from itinerant electrons of metallic nanotubes. At temperatures below 150 K, a dominant narrow signal develops at g = 2.00. By applying multifrequency EPR up to 319 GHz, its inhomogeneous nature was confirmed. This signal is assigned to defects of the carbon network of the tubes. Comparing room temperature EPR spectra of CVD and arc-grown SWNT, we found a much lower concentration of metallic tubes in arc material. No g = 2.07 signals of itinerant spins could be observed, which might be also caused by the high amount of residing catalyst. A drastic increase in nonresonant microwave absorption is observed below 10 K for both types of samples, if a threshold microwave power level is passed. In the same temperature range a drop in EPR intensity is also detected. These observations are taken as evidence for a transition into a superconducting phase of part of the sample. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Unconventional superconductivity and magnetism in Sr2RuO4 and related materials

ANNALEN DER PHYSIK, Issue 3 2004
I. Eremin
Abstract We review the normal and superconducting state properties of the unconventional triplet superconductor Sr2RuO4 with an emphasis on the analysis of the magnetic susceptibility and the role played by strong electronic correlations. In particular, we show that the magnetic activity arises from the itinerant electrons in the Ru d -orbitals and a strong magnetic anisotropy occurs (,+- < ,zz) due to spin-orbit coupling. The latter results mainly from different values of the g -factor for the transverse and longitudinal components of the spin susceptibility (i.e. the matrix elements differ). Most importantly, this anisotropy and the presence of incommensurate antiferromagnetic and ferromagnetic fluctuations have strong consequences for the symmetry of the superconducting order parameter. In particular, reviewing spin fluctuation-induced Cooper-pairing scenario in application to Sr2RuO4 we show how p -wave Cooper-pairing with line nodes between neighboring RuO2 -planes may occur. We also discuss the open issues in Sr2RuO4 like the influence of magnetic and non-magnetic impurities on the superconducting and normal state of Sr2RuO4. It is clear that the physics of triplet superconductivity in Sr2RuO4 is still far from being understood completely and remains to be analyzed more in more detail. It is of interest to apply the theory also to superconductivity in heavy-fermion systems exhibiting spin fluctuations. [source]