UScholar Works
 
Filters: Department: "Physics" Collection: "ir_uspace"
426 - 450 of 924
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CreatorTitleDescriptionSubjectDate
426 Vardeny, Zeev ValentineMechanism for photogeneration of charge carriers in polyacetyleneIn light of new experimental observations, a mechanism for the photogeneration of charge carriers in trans-polyacetylene is presented. By way of introduction, we discuss the qualitative changes in the picture of charged-soliton photogeneration that are expected due to the inclusion of electron corre...Photogeneration; Charge carriers; Photocarriers1984-07
427 Lupton, John MarkMechanisms of spin-dependent dark conductivity in films of a soluble fullerene derivative under bipolar injectionWe report room-temperature pulsed electrically detected magnetic resonance measurements of the dark conductivity of films of the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) under bipolar (electron-hole) and unipolar (electron-rich) injection conditions. Directly after mate...2014-01-01
428 Vardeny, Zeev Valentine; Raikh, Mikhail E.Mesoscopic cooperative emission from a disordered systemWe study theoretically the cooperative light emission from a system of N»1 classical oscillators confined within a volume with spatial scale L much smaller than the radiation wavelength λο=2rrc/ω0. We assume that the oscillator frequencies are randomly distributed around a central frequency ω...Mesoscopic cooperative emission; Disordered systems; Oscillators2000-05
429 Mishchenko, EugeneMesoscopic spin-Hall effect in 2D electron systems with smooth boundariesThe spin-Hall effect in a ballistic 2D electron gas with Rashba-type spin-orbit coupling and smooth edge confinement is studied. We predict that the interplay of semiclassical electron motion and quantum dynamics of spins leads to several distinct features in spin density along the edge that origina...Spin- Hall effect; 2D electron systems2009-05
430 Vardeny, Zeev ValentineMethod for direct determination of the effective correlation energy of defects in semiconductors: optical modulation spectroscopy of dangling bondsThe optical modulation technique is used for direct determination of energy levels and the effective correlation energy U/eff of dangling-bond defects. With an accuracy of 0.1 eV we found for the dangling-bond defect in α-Si:H, f/e f f=0.5 eV; in α-As2S3, £/e f f= - 1.0 eV; in As2Se3, Ueff = -0.7...Dangling bonds; Correlation energy1985-04
431 Williams, Clayton C.Micromachined submicrometer photodiode for scanning probe microscopyA submicrometer photodiode probe with a sub-50 nanometer tip radius has been developed for optical surface characterization on a nanometer scale. The nanoprobe is built to detect subwavelength optical intensity variations in the near field of an illuminated surface. The probe consists of an Al-Si...Submicrometer; Photodiode; Scanning probe microscopy; Nanoprobe1995
432 Williams, Clayton C.Micromachined submicrometer photodiode for scanning probe microscopyA submicrometer photodiode probe with a sub-50 nanometer tip radius has been developed for optical surface characterization on a nanometer scale. The nanoprobe is built to detect subwavelength optical intensity variations in the near field of an illuminated surface. The probe consists of an Al-Si Sc...Submicrometer photodiode; Scanning probe microscopy; Nanobrobes1995
433 Symko, Orest GeorgeMicrowave absorption in the superconducting and normal phases of Y-Ba-Cu-OMicrowave absorption in a dc magnetic field up to 12 kG, attributed to nonequilibrium contributions to the ac susceptibility, appears at Tc as the sample is cooled. ESR measurements of YBa-Cu-O show that Cu2+ exists only in the fraction of the sample which is not superconducting in a distorted octa...Microwave absorption; Superconducting phase; YBCO; High Tc1987-08
434 Vardeny, Zeev Valentine; Nahata, AjayMidinfrared optical response and thermal emission from plasmonic lattices on Al filmsWe studied the midinfrared optical transmission and thermal light emission spectra of subwavelength hole arrays in the form of square lattice with 4 µm periodicity (plasmonic lattice) in aluminum films deposited on silicon substrates. The optical transmission of these films showed temperature inde...Plasmonic lattices; Midinfrared optical response; Thermal emission; Surface plasmon polaritons; Anomalous transmission; Extraordinary optical transmission; EOT2007-11
435 Mishchenko, EugeneMinimal conductivity in graphene: interaction corrections and ultraviolet anomalyConductivity of a disorder-free intrinsic graphene is studied to the first order in the long-range Coulomb interaction and is found to be ? = ?0(1+0.01g), where g is the dimensionless ("fine structure") coupling constant. The calculations are performed using three different methods: i) electron pola...Optical conductivity2008-07-01
436 Mattis, Daniel C.Mobility gap and anomalous dispersionIt is shown that anomalous dispersion of quasiparticles leads to nonpropagating states. Therefore regions of anomalous dispersion define a sort of "mobility gap." Using the coherent-potential approximation, we calculate the conditions for obtaining such a mobility gap in a disordered binary alloy. J...Mobility gap; Disordered media; Quasiparticles1973-09
437 Williams, Clayton C.Modeling and experimental investigation of cantilever dynamics in force detected single electron tunnelingThe dynamic response of a voltage biased oscillating cantilever probe is investigated through experimental and theoretical analysis as it approaches a dielectric surface. When the tip reaches the appropriate gap single electron tunneling events are detected between the metallic tip and the surface. ...Oscillating cantilever probe; Electron tunneling2004
438 Boehme, ChristophModulation frequency dependence of continuous-wave optically/electrically detected magnetic resonanceContinuous-wave optically and electrically detected magnetic resonance spectroscopy (cwODMR/cwEDMR) allow the investigation of paramagnetic states involved in spin-dependent transitions, like recombination and transport. Although experimentally similar to conventional electron spin resonance (ESR), ...2012-01-01
439 Ailion, David CharlesMolecular reorientations in the ordered phases of KCN and NaCN studied by NMRWe have measured 13C and 23Na NMR spin-lattice relaxation times as a function of temperature in KCN and NaCN in order to study the head-to-tail reorientations of the CN- molecules in the two low-temperature ordered phases. We have combined our data with those of dielectric-response and ionic-thermal...Spin; Interactions; Fluctuations1984
440 Lupton, John MarkMolecular thermometer based on long-lived emission from platinum octaethyl porphyrinA highly sensitive molecular thermometer based on platinum octaethyl porphyrin, which can be employed in a range of environments, is presented. The thermal activation of the emission spectrum results in a change in emission intensity by an order of magnitude over a temperature range of 45 K about ro...Molecular thermometer; Platinum octaethyl porphyrin2002
441 Mattis, Daniel C.Molecular-field theory with correlationsWe derive an improved molecular-field theory for spins 1/2 from first principles. Formulas are obtained for use in cases when the fields, bonds, or occupation of the sites are random variables.Molecular-field theory; Spin glasses1979-05
442 DeTar, CarletonMomentum spectrum of hadronic secondaries in the multiperipheral modelMotivated by a simplified multiperipheral model, we formulate a general qualitative description of the momentum spectrum of secondaries, resulting from a collision of two hadrons at high energies. Arguing from two fundamental multiperipheral concepts, (a) that transverse momenta are limited and (b...Secondaries; Multiperipheral model; Fireballs1971-01
443 Lupton, John MarkMonitoring surface charge migration in the spectral dynamics of single CdSe∕CdS nanodot/nanorod heterostructuresSpherical CdSe nanocrystals capped by a CdS rod-like shell exhibit interesting spectral dynamics on the single particle level. Spectral boxcar averaging reveals a high degree of correlation between the emission energy, spectral linewidth, phonon coupling strength, and emission intensity of the singl...Surface charge migration; Spectral dynamics; CdSe; CdS; Nanodot; Nanorod2005-11
444 Lupton, John MarkMonitoring surface charge movement in single elongated semiconductor nanocrystalsWe demonstrate a universal correlation between the spectral linewidth and position of the excitonic transition in the spectral jitter observed from single elongated colloidal quantum dots. Breaking the symmetry of electron and hole confinement as well as of the spatial directions for surface charge ...Surface charge movement; Spectral linewidth; Excitonic transition; Spectral jitter; Colloidal nanocrystals2004-10
445 Wu, Yong-ShiMott transition in an anyon gasWe introduce and analyze a lattice model of anyons in a periodic potential and an external magnetic field, which exhibits a transition from a Mott insulator to a quantum Hall fluid. The transition is characterized by the anyon statistics a, which can vary between fermions, a = 0, and bosons, ct - 1...Anyon gas; Periodic potentials; Mott transition1993-11
446 Wu, Yong-ShiMoyal representation of the string field star product in the presence of a B backgroundIn this paper we show that in the presence of an antisymmetric tensor B background, Witten's star algebra for open string fields persists to possess the structure of a direct product of commuting Moyal pairs. The interplay between the noncommutativity due to three-string overlap and that due to the ...String theory; Moyal pairs; Moyal structure; Noncommutativity2003-06
447 Symko, Orest GeorgeMulti-fluxon steps in long Josephson junctions and their application to oscillatorsStudies of long NbN Josephson junctions of the overlap type in the presence of an external magnetic field show constant voltage steps, of the Fiske type, and large voltage steps. The latter are attributed to multifluxon resonances within the cavity of the junction. The multifluxon steps correspond t...NbN; Multi-fluxon steps; Oscillators1991-03
448 Dawson, KyleMulti-wavelength study of XMMU J2235.3-2557: the most massive galaxy cluster at z > 1The galaxy cluster XMMU J2235.3−2557 (hereafter XMM2235), spectroscopically confirmed at z = 1.39, is one of the most distant X-ray selected galaxy clusters. It has been at the center of a multi-wavelength observing campaign with ground and space facilities. Aims. We characterize the galaxy popula...XMMU J2235.3-2557; XMM2235; X-rays; Redshift2009-12
449 Mattis, Daniel C.Multicomponent polaronBy a slight modification of the Fröhlich Hamiltonian (the introduction of an internal quantum number) we reduce the polaron problem to the solution of a continued fraction, even at finite temperature. We analyze both the stationary states and the resonances (in one- and three-dimensional versions o...Ground-state energy; Coupling constant; Fröhlich model; Finite temperature1991-10
450 Wu, Yong-ShiMultiparticle quantum mechanics obeying fractional statisticsWe obtain the rule governing many-body wave functions for particles obeying fractional statistics in two (space) dimensions. It generalizes and continuously interpolates the usual symmetrization and antisymmetrization. Quantum mechanics of more than two particles is discussed and some new features a...Multiparticle quantum mechanics; Fractional statistics1984-07
426 - 450 of 924