UScholar Works
 
Filters: Department: "Physics" Collection: "ir_uspace"
176 - 200 of 924
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CreatorTitleDescriptionSubjectDate
176 Mattis, Daniel C.Effect of spin variables and exciton motion on ground-state properties of the "trionWe solve a quantum three-body problem involving two holes and a single electron ("trion") in a two-band Hubbard model. The particles' spin and the exciton hopping matrix element are all included. We compare the results with those of a previous paper, in which these additional complications were abs...Three-body problem; Trion; Bond energies1983-03
177 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
178 Ailion, David CharlesEffect of the translational diffusion mechanism on the low-field NMR spin-lattice relaxation time in the rotating reference frame: calculation of order parameterThe effect of the translational-diffusion mechanism on the low-field NMR spin-lattice relaxation time in the rotating reference frame is calculated for simple cubic, body-centered cubic, and face-centered cubic lattices. The results of these calculations suggest a new method for determining the pref...NMR; Nuclear magnetic resonance; Lattices; Relaxation time1968
179 Vardeny, Zeev ValentineThe effects of charge injection in single-wall carbon nanotubes studied by charge-induced absorptionWe studied direct charge injection in a heterogeneous film of single-wall carbon nanotubes using the technique of charge-induced absorption. We found that the injected charges screen the excitons in the semiconducting tubes, reducing their binding energy and transferring oscillator strength from the...2011
180 Dawson, KyleThe effects of charge transfer inefficiency (CTI) on galaxy shape measurementsWe examine the effects of charge transfer inefficiency (CTI) during CCD readout on the demanding galaxy shape measurements required by studies of weak gravitational lensing. We simulate a CCD readout with CTI such as that caused by charged particle radiation damage in space-based detectors. We verif...2010
181 Mattis, Daniel C.Effects of orbital degeneracy on a magnetic impurity in a nonmagnetic metalWe study the Green's-function equations for a version of the two-orbital Anderson model of a magnetic impurity, in an approximation scheme that displays the logarithmic anomalies and enables the Kondo temperature Tĸ to be calculated as a function of the parameters. The nature of the solutions is ex...Orbital degeneracy; Magnetic impurities; Nonmagnetic metal; Kondo temperature; Anomalous resonances1969-02
182 Gondolo, PaoloEffects of the Sagittarius dwarf tidal stream on dark matter detectorsThe Sagittarius dwarf tidal stream may be showering dark matter onto the solar neighborhood, which can change the results and interpretation of direct detection searches for weakly interacting massive particles (WIMPs). Stars in the stream may already have been detected in the solar neighborhood, an...Sagittarius dwarf galaxy; Sgr stream; WIMP; Weakly interacting massive particles2004-03
183 Vardeny, Zeev ValentineEfficiency enhancement of an organic light-emitting diode with a cathode forming two-dimensional periodic hole arrayWe fabricated an organic light-emitting diode using a ∏-conjugated polymer emissive layer sandwiched between two semitransparent electrodes: an optically thin gold film anode, whereas the cathode was in the form of an optically thick aluminum (Al) film with patterned periodic subwavelength two-dim...pi-conjugated polymers; Organic light-emitting diode; OLED2005
184 Lupton, John MarkEfficient dipole-dipole coupling of Mott-Wannier and Frenkel excitons in (Ga,In)N quantum well/polyfluorene semiconductor heterostructuresWe investigate interactions between Mott-Wannier (MW) and Frenkel excitons in a family of hybrid structures consisting of thin organic (polyfluorene) films placed in close proximity (systematically adjusted by GaN cap layer thickness) to single inorganic [(Ga, In)N/GaN] quantum wells (QWs). Charac...Mott-Wannier; Frenkel; Excitons; Dipole-dipole coupling; Semiconductor heterostructures2007-07
185 Mattis, Daniel C.Eigenfunction localization in dilute lattices of various dimensionalitiesAs a fraction of bonds p is removed from a lattice, we find a threshold PQ above which all eigenstates are nonpropagating (Anderson localized). This occurs well before the classical percolation threshold. For example, in two dimensions where the classical threshold is pc = 1/2 , we find PQ = 0.Eigenstates; Dilute lattices1981-05
186 Bromley, Benjamin C.Eigenspectral computtations for linear gravity and nonlinear toy modelsThe periodic standing-wave approach to binary inspiral assumes rigid rotation of gravitational fields and hence helically symmetric solutions. To exploit the symmetry, numerical computations must solve for "helical scalars," fields that are functions only of corotating coordinates, the labels on the...Binary black holes; General relativity; Standing wave2006
187 Mattis, Daniel C.Eigenstates of excitons near a surfaceThe exact eigenstates and energies of an electron and a hole of equal effective masses, with an attractive δ-function interaction and hard-wall repulsion at the surfaces of a solid, are classified and obtained explicitly for a solid of arbitrary thickness. Both bound and scattering states of the e...Eigenstates; Frenkel excitons1978-10
188 Mattis, Daniel C.Eigenstates of N excitons and one holeWe solve for the eigenstates and energy eigenvalues of N immobile Frenkel excitons (a relatively trivial proposition) and of N such excitons plus one hole (which for large N can only be done in one dimension). We also guess that a charged globule, consisting of N excitons and O(N) holes, can be stab...Eigenstates; Frenkel excitons; Many-body problem1983-04
189 Vardeny, Zeev ValentineElectrical and optical studies of gap states in self-assembled molecular aggregatesWe fabricated a variety of two-terminal devices using self-assembled monolayers (SAM) of solid-state mixtures comprised of molecular "wires" [1,4-methane-benzenedithiol (Me-BDT)] and molecular insulator "spacers" [1-pentanethiol], which were prepared at various molar concentrations ratio, r of wires...Gap states; Self-assembled molecular aggregates2007
190 Boehme, ChristophElectrical detection of coherent 31P spin quantum statesIn recent years, a variety of solid-state qubits has been realized, including quantum dots [1, 2], superconducting tunnel junctions [3, 4] and point defects [5, 6]. Due to its potential compatibility with existing microelectronics, the proposal by Kane [7, 8] based on phosphorus donors in Si has als...Spin quantum states; Qubits; Rabi flops2006-11-19
191 Boehme, ChristophElectrical detection of spin coherence in siliconExperimental evidence is presented showing that photocurrents in silicon can be used as highly sensitive readout probes for coherent spin states of localized electrons, the prime candidates for quantum bits in various semiconductor based quantum computer concepts. Conduction electrons are subjected ...Spin coherence; Electronic transitions; Rabi oscillation2003-12
192 Vardeny, Zeev ValentineElectroabsorption spectroscopy of luminescent and nonluminescent ∏-conjugated polymersWe have measured the quadratic electroabsorption (EA) spectrum of a variety of soluble luminescent and nonluminescent p-conjugated polymer films in the spectral range of 1.5-4.5 eV. The luminescent polymers include MEH and DOO derivatives of poly(phenylene-vinylene), poly(phenylene ethylene), and ...Electroabsorption spectroscopy; pi-conjugated polymers1997-12
193 Vardeny, Zeev ValentineElectroabsorption spectroscopy of single walled nanotubesWe have measured the electric field modulated absorption of a sample of single-walled nanotubes (SWNT) suspended in a solid polyvinyl alcohol matrix. The electroabsorption (EA) spectrum roughly follows the first derivative of the absorption with respect to photon energy, scales quadratically with t...Electroabsorption spectroscopy; Single-walled nanotubes; SWNT2005
194 Vardeny, Zeev ValentineElectromodulated photoinduced absorption; a new spectroscopy in ∏-conjugated polymer/C60-blendsWe have applied the electromodulated photoinduced absorption (EPA) technique to a variety of C 6 0 -doped and pristine luminescent conducting polymer films. EPA measures the electric field-related change of the absorption in the sample as a result of above-gap illumination. An electric field leads t...Electromodulated photoinduced absorption; EPA; C60 doping; Electromodulated photoluminescence; EPL; Polaron pair polarizability1997
195 Vardeny, Zeev ValentineElectromodulation of charge-transfer photoexcitations in pristine and C60-doped conjugated polymersWe study the effect of an electric field of up to 100 kV/cm on photoexcitations in pristine and C60-doped p-conjugated polymers by electromodulated photoinduced absorption (EPA). In EPA, we measure changes in the photoinduced absorption of a polymer film induced by an electric field. The dominant ...Electromodulation; Charge-transfer photoexcitations; Photoinduced absorption; pi-conjugated polymers; Electromodulation spectroscopy1999-04
196 Mattis, Daniel C.Electron states in random alloys with short-range orderWe present an accurate and economical iterative method of calculating the energy levels of a disordered or partly ordered random alloy. Results presented for one- and three-dimensional simple cubic lattices compare favorably with exact calculations. We also present the systematic effects of partia...Random alloys; Density of state1977-04
197 Williams, Clayton C.Electron tunneling detected by electrostatic forceA method is introduced for measuring the tunneling of electrons between a specially fabricated scanning probe microscope tip and a surface. The technique is based upon electrostatic force detection of charge as it is transferred to and from a small (10217 F) electrically isolated metallic dot on the...Electrons; Tunneling events; Electrostatic force microscopy2000
198 Mishchenko, EugeneElectron-lattice kinetics of metals heated by ultrashort laser pulsesWe propose a kinetic model of transient nonequilibrium phenomena in metals exposed to ultrashort laser pulses when heated electrons affect the lattice through direct electron-phonon interaction. This model describes the destruction of a metal under intense laser pumping. We derive the system of equa...Electron-lattice kinetics; Thermoconductivity; electron temperature; Lattice deformation1999-01
199 Mattis, Daniel C.Electron-phonon interaction in two dimensions: the case for strong coupling in high-Tc superconductorsA particular model interaction between electrons and acoustic phonons is found to cause electrons to become weakly "self-trapped" for an arbitrary filling factor in d=2, but not in d=1 nor, for different reasons, in d>3. To the extent that electron kinetic energy is reduced in d=2, the electronic in...Strong coupling1987-09
200 Mishchenko, EugeneElectronic Raman scattering in a magnetic fieldRaman scattering in a magnetic field is proposed as a possible method to solve the problem of whether the light scattering in high-Tc superconductors comes from conduction electrons or not. The electronic Raman light scattering in a magnetic field is studied theoretically. The semiclassical approa...Raman scattering1996-01
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