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CreatorTitleDescriptionSubjectDate
226 Wu, Yong-ShiScale and conformal invariance in Chern-Simons-matter field theoryWe study perturbative renormalization of Dsss3 Chern-Simons gauge theory coupled to scalar and fermionic matter. We show that in the non-Abelian case the coefficient of the Chern-Simons term has infinite renormalization and that both the matter and the non-Abelian gauge fields acquire nonvanishing ...Chern-Simons gauge theory; Renormalization1991-09
227 DeTar, CarletonQCD thermodynamics with an improved lattice actionWe have investigated QCD with two flavors of degenerate fermions using the Symanzik-improvement program for both the gauge and fermion actions. Our study focuses on the deconfinement transition on an Nt=4 lattice. Having located the thermal transition, we performed zero temperature simulations nea...Wilson fermions; Polyakov loop; Chiral symmetry; Phase transitions1997-11
228 Vardeny, Zeev ValentineBelow-gap excitation of ∏-conjugated polymer-fullerene blends: implications for bulk organic heterojunction solar cellsWe used a variety of optoelectronic techniques such as broadband fs transient and cw photomodulation spectroscopies, electroabsorption, and short-circuit photocurrent in bulk heterojunctions organic solar cells for studying the photophysics in ∏-conjugated polymer-fullerene blends with below-gap...pi-conjugated polymers; Fullerene blends; Below-gap excitations; Bulk heterojunctions; Bulk organic heterojunction solar cells; Photophysics2008-07
229 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
230 Vardeny, Zeev ValentineUltrafast electronic and acoustic effects in conducting polymersThe polarized picosecond pump and probe technique with 50 fsec resolution has been used to generate and detect electronic excitations and propagation of ultrasonic phonons in thin films of oriented and unoriented polyacetylene and polythiophene. We found that the photoexcitations are instantaneou...Ultrafast electronic effects; Ultrafast acoustic effects; Polarized picosecond pump; Pump and probe technique; Ultrasonic phonons1990
231 Lupton, John MarkTime-gated electroluminescence spectroscopy of polymer light-emitting diodes as a probe of carrier dynamics and trappingWe present time-gated electroluminescence (EL) spectroscopy of a polyfluorene-based conjugated polymer. The technique is shown to be sensitive enough to pick out impurity emission orders of magnitude weaker than the cw emission. By considering the temperature dependence of the delayed emission spect...Time-gated electroluminescence spectroscopy; Carrier dynamics; Trapping; Delayed emission2002-04
232 Gondolo, PaoloFluid interpretation of Cardassian expansionA fluid interpretation of Cardassian expansion is developed. Here, the Friedmann equation takes the form H2=g(ρM) where ρM contains only matter and radiation ~no vacuum!. The function g(ρM) returns to the usual 8πM /(3mpl 2 ) during the early history of the Universe, but takes a different form...Cardassian expansion; Friedmann equation2003-09
233 Vardeny, Zeev ValentineSpin-dependent delayed luminescence from nongeminate pairs of polarons in ∏-conjugated polymersWe measured cw photoinduced absorption (PA) and spin- 1 2 PA- and photoluminescence detected magnetic resonance (PADMR and PLDMR, respectively) in films of two representative p-conjugated polymers; poly(phenylene-vinylene) and polythiophene. From the dependences of the polaron PA and PLDMR on the ...pi-conjugated polymers; Nongeminate pairs; Spin-dependent delayed luminescence; Photoinduced absorption; Poly(phenylene-vinylene)2002-12
234 Williams, Clayton C.; Stringfellow, Gerald B.Effect of substrate misorientation on ordering in Ga0.5In0.5POrdering produced in Gao.5Ino.5P epitaxial layers grown by OMVPE can be controlled by variations in the substrate misorientation as well as the growth temperature and the growth rate. The ordering produced at a growth temperature of 620°C and a relatively low growth rate of 0.5 /μm/hr is found to ...Ga0.5In0.5P; Epitaxial layers; Epitaxial growth; OMVPE1994
235 Symko, Orest GeorgeSpin freezing below the nearest-neighbor percolation concentration in Cd1-xMnxTe and Cd1-xMnxSeThe very-low-temperature magnetization of Cdi_xMnxTe and Cdj-xMnxSe alloys shows spinglass behavior for concentrations below the nearest-neighbor percolation limit. This is attributed to short-range exchange and dipolar interactions. New magnetic phase diagrams for both systems are presented.Spin freezing; Cd1-xMnxTe; Cd1-xMnxSe; Very-low-temperature magnetization; Spin-glass behavior1986-05
236 Gerton, JordanOptimizing contrast of tip-enhanced fluorescence microscopy for imaging high-density samplesQuantum dots are imaged using tip-enhanced fluorescence microscopy. Optimization of the operation parameters leads to high-contrast images of high-density samples and a novel photon analysis improves contrast further.2007-05
237 Williams, Clayton C.High resolution photothermal laser probeAt frequencies near 1 GHz, the acoustic wavelength in argon gas becomes half that of visible light, making possible collinear Bragg scattering of laser light by the sound. This acousto-optic interaction has been used to detect photothermally generated acoustic power at the surface of solids. This ne...Photothermal laser probe; Silicon wafer1984
238 Williams, Clayton C.Direct imaging of SiO2 thickness variation on Si using modified atomic force microscopeFabrication techniques of metal-oxide-semiconductor ~(MOS) transistors have been improved very rapidly during the last several decades. With this trend, scaling down of MOS transistors is necessary to improve the speed of circuits and the packing density of discrete devices. Both lateral and vertic...Silicon dioxide; Oxide layer; Phosphorus ions; Oxide capacitance; Dopant profile1996-03-01
239 Gerton, JordanVibrational relaxation of ultracold lithium dimersLaser cooling and trapping of aloms has enabled some of the most exiting recent advances in atomic physics, including the achievement of Bose-Einstein condensation (BEC). efforts are now underway to trap ultracold molecules in order to study chemical reactions and to investigale BEC experiments, the...2000-01-01
240 Vardeny, Zeev Valentine; Raikh, Mikhail E.Excitations in photonic crystals infiltrated with polarizable mediaLight propagation in a photonic crystal with incomplete band gap, infiltrated with polarizable molecules is considered. We demonstrate that the interplay between the spatial dispersion caused by Bragg diffraction and polaritonic frequency dispersion gives rise to alternative propagating excitation...Polarizable media; Light propagation; Bragg diffraction; Excitations2001-06
241 Sokolsky, PierreSearch for > 200 TeV photons from Cygnus X-3 in 1988 and 1989Over a period of 16 months from April 1988 to August 1989, we have monitored the flux of cosmic-ray showers with energies above 2X 10^14 eV. We used a two-level array of scintillators covering an area of 3 X 10^4 m2 . Counters on the surface measure the size and direction of each shower while counte...Cygnus X-3; Extensive air showers1990-07
242 Mattis, Daniel C.Theory of superexchange in CuO2The limit method allows exact analysis of low-lying electronic states in a strong-coupling model Cu02 plane. We extend it to nonorthogonal orbitals and fit to a t-t'-J model. The superexchange parameter is J = g32t*, with the unit of energy and g3 a lumped parameter.Copper oxides; Superexchange1995-12
243 Sokolsky, PierreComparison of air fluorescence and ionization measurements of E.M. shower depth profiles: test of a UHECR detector techniqueMeasurements are reported on the fluorescence of air as a function of depth in electromagnetic showers initiated by bunches of 28.5 GeV electrons. The light yield is compared with the expected and observed depth profiles of ionization in the showers. It validates the use of atmospheric fluorescence...Air fluorescence; Electromagnetic shower; Ultra-high energy cosmic rays; Ionization2006-02
244 Wu, Yong-ShiResonant above-threshold ionization at quantized laser intensitiesWe argue that quantum electrodynamics dictates resonance phenomena in multiphoton processes as the laser intensity varies. A perturbation theory is developed in which the coupling between an electron and the second quantized laser mode is treated nonperturbatively. As an example, we predict that th...Laser field; Volkov states2000-03
245 Ailion, David CharlesNMR observations of molecular motions and Zeeman-quadrupole cross relaxation in 1,2- difluorotetrachloroethaneWe report measurements of "F NMR relaxation times Tu Tlf, TID, and T2 in the plastic crystal CFCL2-CFCL2 . From the data near the melting point, we obtain the jump time for translational selfdiffusion. At lower temperatures, we observe on the cold side of the T, and Tif minima an unusual field depe...NMR; Nuclear magnetic resonance; Order-disorder; Diffusion1979
246 Williams, Clayton C.; Huang, YufengDirect comparison of cross-sectional scanning capacitance microscope dopant profile and vertical secondary ion-mass spectroscopy profileThe scanning capacitance microscope (SCM) has been shown to be useful for quantitative 2D dopant profiling near the surface of silicon. An atomic force microscope is used to position a nanometer scale tip at a silicon surface, and local capacitance change is measured as a function of sample bias. A ...Oxide capacitance; Dopant profile; Oxide layer; Scanning capacitance microscopy1996-01
247 Lupton, John MarkExperimental evidence for exciton scaling effects in self-assembled molecular wiresResonant Rayleigh scattering from self-assembled one-dimensional molecular J-aggregate wires reveals a distinct dependence of the exciton energy on the width of lateral extension. For the J aggregates used in this study, strong in-line dipole coupling leads to a delocalization of the exciton wave fu...Exciton scaling effects; Molecular wires; J-aggregate wires; Quantum wires2004-12
248 Mishchenko, EugeneSpin current and polarization in impure two-dimensional electron systems with spin-orbit couplingWe derive the transport equations for two-dimensional electron systems with Rashba spin-orbit interaction and short-range spin-independent disorder. In the limit of slow spatial variations, we obtain coupled diffusion equations for the electron density and spin. Using these equations we calculate el...Spin-orbit coupling; Spin current2004-11
249 Dawson, KyleTechnology development for 4k x 4k, back-illuminated, fully depleted scientific CCD imagersWe have developed scientific charge-coupled devices (CCDs) that are fabricated on high-resistivity, n-type silicon substrates, and have demonstrated fully depleted operation for substrate thicknesses of 200-675 μm with formats as large as 2048 × 4096 (15 μm pixels) and 3512 × 3512 (10.5 μm pix...Gettering2007-10
250 Vardeny, Zeev ValentineLattice dynamics of CuClA satisfactory fit for CuCl phonon dispersion relations is obtained for the first time. This fit is achieved by modifying the branch assignment of a few 2 phonons and by applying a double-shell model to fit the observed phonon data.CuCl; Phonon dispersion relations1975-06
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