UScholar Works
 
Filters: Journal Title: "Physical Review Letters" Collection: "ir_uspace"
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CreatorTitleDescriptionSubjectDate
1 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
2 Mishchenko, EugeneCharge response function and a novel plasmon mode in graphenePolarizability of noninteracting 2D Dirac electrons has a 1 1 / √qv-ω singularity at the boundary of electron-hole excitations. The screening of this singularity by long-range electron-electron interactions is usually treated within the random phase approximation. The latter is exact only in the ...Excitons; Random phase approximation2008-04
3 Gondolo, PaoloDark matter and the first stars: a new phase of stellar evolutionA mechanism is identified whereby dark matter (DM) in protostellar halos dramatically alters the current theoretical framework for the formation of the first stars. Heat from neutralino DM annihilation is shown to overwhelm any cooling mechanism, consequently impeding the star formation process and ...Dark stars2008-02
4 Rogachev, AndreyDetermination of the superconductor-insulator phase diagram for one-dimensional wiresWe establish the superconductor-insulator phase diagram for quasi-one-dimensional wires by measuring a large set of MoGe nanowires. This diagram is roughly consistent with the Chakravarty-Schmid-Bulgadaev phase boundary, namely, with the critical resistance being equal to RQ ¼ h=4e2. Deviations fr...One-dimensional wires; Superconductor-insulator phase diagram; MoGe; Chakravarty-Schmid-Bulgadaev; Phase boundary2008-11
5 Stringfellow, Gerald B.; Zhu, Jing Yi; Liu, FengDual-surfactant effect to enhance p-type doping in III-V semiconductor thin filmsSurfactant effects are usually achieved by the addition of a single surface element. We demonstrate by first-principles calculations a dual-surfactant effect of Sb and H on enhancing Zn doping in organometallic vapor phase epitaxially grown GaP thin films. The combined effects of Sb and H lower sig...Surfactants; p-type doping2008-11
6 Sokolsky, PierreFirst observation of the Greisen-Zatsepin-Kuzmin suppressionThe High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called the GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement of the flux of ultrahigh energy cosmic rays shows a sharp suppression at an energy of 6 x 10^1...Extensive air showers; Suppression; Energy spectrum; Fluorescence; GZK cutoff2008-03
7 Boehme, ChristophLong-lived spin coherence in silicon with an electrical spin trap readoutPulsed electrically detected magnetic resonance of phosphorous (31P) in bulk crystalline silicon at very high magnetic fields (B0 > 8:5 T) and low temperatures (T = 2:8 K) is presented. We find that the spin-dependent capture and reemission of highly polarized (>95%) conduction electrons by equall...Spin coherence2008-11
8 Miller, Joel Steven; Epstein, Arthur J.Magnetic bistability and nucleation of magnetic bubbles in a layered 2D organic-based magnet [Fe(TCNE)(NCMe)2][FeC14]The 2D layered organic-based magnet [Fe(TCNE)(NCMe)2][FeCl4] (TCNE ¼ tetracyanoethylene) exhibits a unique macroscopic magnetic bistability between the field-cooled and zero-field-cooled states, which cannot be explained by either superparamagnetic behavior or spin freezing due to spin glass orde...Organic-based magnets; Tetracyanoethylene; Magnetic bistability; Nucleation2008-11
9 Vardeny, Zeev ValentineMagnetic field effects in ∏-conjugated polymer-fullerene blends: evidence for multiple componentsWe studied magnetoconductance (MC) and magnetoelectroluminescence (MEL) in organic diodes from blends of ∏-conjugated polymers and fullerenes at various concentrations, c. The MC response is composed of several components that depend on the applied bias voltage and c. A dominant positive low-field...pi-conjugated polymers; Fullerene blends; Magnetic field effects; Magnetoconductance; Magnetoelectroluminescence; MC; MEL; Organic magnetoresistance; OMAR; Organic diodes2008-12
10 Sokolsky, PierreObservation of the suppression of the flux of cosmic rays above 4×10^19eVThe energy spectrum of cosmic rays above 2.5 x 10^18 eV, derived from 20 000 events recorded at the Pierre Auger Observatory, is described. The spectral index γ of the particle flux, J∞ E-γ, at energies between 4 x 10^18 eV and 4 x 10^19 eV is 2.69 ± 0.02(stat) ± 0.06(syst), steepening to 4.2 ...Extensive air showers; Energy spectrum; Fluorescence; Suppression2008-08
11 Mishchenko, Eugene; Raikh, Mikhail E.Scattering of plasmons at the intersection of two metallic nanotubes: implications for tunnelingWe study theoretically the plasmon scattering at the intersection of two metallic carbon nanotubes. We demonstrate that, for a small angle of crossing θ « 1, the transmission coefficient is an oscillatory function of λ / θ where λ is the interaction parameter of the Luttinger liquid in an indi...2008-12
12 Gerton, JordanScattering of plasmons at the intersection of two metallic nanotubes: implications for tunnelingWe study theoretically the plasmon scattering at the intersection of two metallic carbon nanotubes. We demonstrate that, for a small angle of crossing θ « 1, the transmission coefficient is an oscillatory function of θ / λ, where ω is the interaction parameter of the Luttinger liquid in an ind...2008-12
13 Liu, FengTheory of directed nucleation of strained islands on patterned substratesWe develop a theoretical model to elucidate the nucleation of strained islands on patterned substrates. We show that island nucleation is directed to the preferred sites by a much lower energy barrier and smaller critical size. Strain relaxation directs island nucleation to the bottom of a pit rat...Directed nucleation; Strained islands; Patterned substrates2008-11
14 Vardeny, Zeev ValentineUltrafast response of surface electromagnetic waves in an aluminum film perforated with subwavelength hole arraysThe ultrafast dynamics of surface electromagnetic waves photogenerated on aluminum film perforated with subwavelength arrays of holes was studied in the visible spectral range by the technique of transient photomodulation with ~100 fs time resolution. We observed a pronounced blueshift of the resona...Subwavelength hole arrays; Nanohole arrays; Transient photomodulation; Plasmonic lattices; Surface electromagnetic waves; SEW; Periodic subwavelength arrays2008-02
15 Saam, BrianUniversal long-time behavior of nuclear spin decays in a solidMagnetic resonance studies of nuclear spins in solids are exceptionally well suited to probe the limits of statistical physics. We report experimental results indicating that isolated macroscopic systems of interacting nuclear spins possess the following fundamental property: spin decays that start ...Nuclear spin decays; Hyperpolarized solid xenon; Chaos2008-08
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