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Articles 32251 - 32280 of 36555
Full-Text Articles in Physical Sciences and Mathematics
Interface Alloying And Magnetic Properties Of Fe/Rh Multilayers, K. Hanisch, W. Keune, R.A. Brand, Christian Binek, Wolfman Kleemann
Interface Alloying And Magnetic Properties Of Fe/Rh Multilayers, K. Hanisch, W. Keune, R.A. Brand, Christian Binek, Wolfman Kleemann
Christian Binek Publications
Rh(20 Å)/57Fe(tFe) multilayers with Fe thicknesses tFe of 2, 5, 10, and 15 Å prepared by alternate evaporation in UHV have been investigated by x-ray diffraction (XRD), Mössbauer spectroscopy, and SQUID magnetometry. First- and second-order superstructure Bragg peaks (but no higher-order peaks) in small-angle XRD patterns suggest some compositional modulation. Mössbauer spectra taken at 4.2 K are characterized by a distribution P(Bhf) of hyperfine fields Bhf. Peaks observed in the P(Bhf) curves near 17 and 35 T are assigned to an fcc-RhFe interface alloy (~7–24 at. % Fe) with …
Aligned Two-Phase Magnets: Permanent Magnetism Of The Future? (Invited), Ralph Skomski
Aligned Two-Phase Magnets: Permanent Magnetism Of The Future? (Invited), Ralph Skomski
Ralph Skomski Publications
Micromagnetic calculations are used to investigate coercivity and energy products of magnets consisting of an aligned hard-magnetic skeleton phase and a soft-magnetic phase with high saturation magnetization. Compared to the present-day theoretical limit of 516 W/m3 for single-phase Nd2Fe14B, the energy product in suitable nanostructured Sm2Fe2N3/Fe65Co35 composites is predicted to be as high as 1090 kJ/m3. The influence of the skeleton’s texture and shape is discussed, and aligned nanocrystalline two-phase magnets are compared with remanence-enhanced isotropic magnets. In particular, it is shown how the nucleation-based analytical …
Mössbauer Study Of Permanent-Magnet Materials: Sm2Fe17-XAlX Compounds, I.A. Al-Omari, Sitaram Jaswal, A.S. Fernando, David J. Sellmyer
Mössbauer Study Of Permanent-Magnet Materials: Sm2Fe17-XAlX Compounds, I.A. Al-Omari, Sitaram Jaswal, A.S. Fernando, David J. Sellmyer
David Sellmyer Publications
The Fe57 Mössbauer spectra of Sm2Fe17-xAlx, where x=0, 1.0, 2.0, 3.0, and 4.0, have been measured at room temperature and analyzed. The ternary compounds Sm2Fe17-xAlx have the rhombohedral Th2Zn17 structure. Mössbauer measurements showed that all the compounds studied were ferromagnetic. The average hyperfine field was found to decrease with the increasing aluminum concentration, which is in qualitative agreement with magnetic measurements. The decrease in the average hyperfine field was from 224 kOe at x=0 to 174 kOe at x=4. By fitting the …
Sputtering Pressure Effects And Temperature-Dependent Magnetism Of Co/Pd Multilayers, S.Y. Jeong, Z.S. Shan, P. He, J.X. Shen, Y.B. Zhang, John A. Woollam, David J. Sellmyer
Sputtering Pressure Effects And Temperature-Dependent Magnetism Of Co/Pd Multilayers, S.Y. Jeong, Z.S. Shan, P. He, J.X. Shen, Y.B. Zhang, John A. Woollam, David J. Sellmyer
David Sellmyer Publications
The temperature dependence of the sputtering Ar pressure effects on magnetic properties and the coercivity mechanism of Co(2 Å)/Pd(13 Å) multilayers were studied as the sputtering Ar pressure varied from 3–15 mTorr and the temperature from 300 to 35 K. It is found that the roughness of the interfaces or film surface increases with increasing sputtering pressure, the anisotropy increases with decreasing temperature and increasing Ar pressure and shows a maximum at PAr≃12 mTorr, and the coercivity increases with Ar pressure and shows stronger temperature dependence at higher Ar pressure. The coercivity mechanism was analyzed in terms of …
Thickness Dependence Of The Magnetic And Electrical Properties Of Fe:Sio2 Nanocomposite Films, S.S. Malhotra, Yi Liu, J.X. Shen, Sy_Hwang Liou, David J. Sellmyer
Thickness Dependence Of The Magnetic And Electrical Properties Of Fe:Sio2 Nanocomposite Films, S.S. Malhotra, Yi Liu, J.X. Shen, Sy_Hwang Liou, David J. Sellmyer
Sy-Hwang Liou Publications
Nanocomposite Fe80 (SiO2)20 films with thickness from 150 to 5000 Å have been prepared by rf magnetron sputtering from a composite target. The crystallites in the Fe80 (SiO2)20 films have a bcc structure with the average size of 46–66 Å which was determined by transmission electron microscopy. As indicated by the thickness dependence of resistivity, the stacking and connectivity of the crystallites depend on the thickness of the films. The magnetic properties also depend on the microstructure which changes with the thickness of the films. The magnetic coercivity of the films increases …
Iron Core Formation In Horse Spleen Ferritin: Magnetic Susceptibility, Ph, And Compositional Studies, S. Hilty, B. Webb, Richard B. Frankel, G. D. Watt
Iron Core Formation In Horse Spleen Ferritin: Magnetic Susceptibility, Ph, And Compositional Studies, S. Hilty, B. Webb, Richard B. Frankel, G. D. Watt
Physics
Horse spleen ferritin (HoSF) reconstituted with small iron cores ranging in size from 8 to 500 iron atoms was studied by magnetic susceptibility and pH measurements to determine when the added Fe3+ begins to aggregate and form antiferromagnetically coupled clusters and also to determine the hydrolytic state of the iron at low iron loading. The Evans NMR magnetic susceptibility measurements showed that at iron loadings as low as 8 Fe3+/HoSF, at least half of the added iron atoms were involved in antiferromagnetic exchange interactions and the other half were present as isolated iron atoms with S = …
Surface Core-Level Shifts And Atomic Coordination At A Stepped W(110) Surface, D. Mark Riffe, B. Kim, J. L. Erskine, N. D. Shinn
Surface Core-Level Shifts And Atomic Coordination At A Stepped W(110) Surface, D. Mark Riffe, B. Kim, J. L. Erskine, N. D. Shinn
All Physics Faculty Publications
Core-level 4f7/2 photoemission spectra have been measured from a single, bifacial W crystal, which has both a flat W(110) and a vicinal, stepped W(110) [W(320)] surface. This procedure reduces uncertainties in the quantitative description of peaks in the spectra from W(320). Various analyses, including nonlinear least-squares curve fitting, show that the average surface core-level shift (SCS) for W(320) is only ∼-140 meV, compared to -310 meV for W(110) and that, at a maximum, only two of five terrace rows are isoelectronic to W(110) surface atoms. The absence of a large SCS for the step-edge atoms contradicts earlier interpretations of …
Electron Energy Loss In Oxygen Plasmas, G. A. Victor, John C. Raymond, Jane L. Fox
Electron Energy Loss In Oxygen Plasmas, G. A. Victor, John C. Raymond, Jane L. Fox
Jane L. Fox
The results of calculations of the energy deposition of energetic electrons in oxygen plasmas are given. In a pure oxygen plasma even with large fractional ionization, much of the electron energy results in the production of additional ionization and excited electronic states. Results are given for separate calculations using theoretical and experimental cross sections for the important O I excitations of 1S and 1D because the theoretical and experimental data are not in agreement. These results are useful for understanding the spectra of oxygen-rich supernova remnants.
Matched Optical Solitary Waves For 3-Level And 5-Level Systems, Foek T. Hioe, R. Grobe
Matched Optical Solitary Waves For 3-Level And 5-Level Systems, Foek T. Hioe, R. Grobe
Physics Faculty/Staff Publications
Exact analytic results are presented that give a general solution for a pair of solitary waves which can propagate through a three- and a five-level system with their shapes invariant. These solitary waves vary widely in shape and form: from ones for which the pulses have similar shape to ones which have very different but ''complementary'' shapes. A general type of solitary-wave pair which is insensitive to small perturbations is identified.
Mössbauer, Magnetic, And Electronic-Structure Studies Of Yfe12-XMoX Compounds, I.A. Al-Omari, Sitaram Jaswal, A.S. Fernando, David J. Sellmyer, H.H. Hamdeh
Mössbauer, Magnetic, And Electronic-Structure Studies Of Yfe12-XMoX Compounds, I.A. Al-Omari, Sitaram Jaswal, A.S. Fernando, David J. Sellmyer, H.H. Hamdeh
David Sellmyer Publications
Mössbauer spectra, magnetization measurements, and self-consistent spin-polarized electronic structures of YFe12-xMox, where x=0.5, 1.0, 2.0, 3.0, and 4.0, are reported. The ternary compounds YFe12-xMox have the crystalline tetragonal ThMn12 structure. Analyses of the Mössbauer spectra show that Mo atoms occupy the 8i Fe sites of the ThMn12 structure, in agreement with previous observations. Room-temperature magnetic and Mössbauer measurements show that the compounds with x≤2.0 are ferromagnetic and with x≥3.0 are paramagnetic. Measurements at 25 K show that all the samples are magnetically ordered. The magnetic hyperfine field is …
Measurements Of The (E,E’Pπ-) Reaction On Nuclei In The Nucleon Resonance Region, L Elouadrhiri, R A. Miskimen, J Button-Shafer, P Degtyarenko,, Gerald Alvin Peterson, S Shuvalov, K Wang
Measurements Of The (E,E’Pπ-) Reaction On Nuclei In The Nucleon Resonance Region, L Elouadrhiri, R A. Miskimen, J Button-Shafer, P Degtyarenko,, Gerald Alvin Peterson, S Shuvalov, K Wang
Gerald Alvin Peterson
Nucleon resonances beyond the Δ(1232) have been observed in complex nuclei. Measurements of the (e,e’pπ-) reaction, at an incident energy of 14.5 GeV with 1.1 GeV
Measurements Of The Electric And Magnetic Form Factors Of The Proton From Q2=1.75 To 8.83 (Gev/C)2, L Andivahis, R S. Hicks, R A. Miskimen, Gerald Alvin Peterson, S Rokni
Measurements Of The Electric And Magnetic Form Factors Of The Proton From Q2=1.75 To 8.83 (Gev/C)2, L Andivahis, R S. Hicks, R A. Miskimen, Gerald Alvin Peterson, S Rokni
Gerald Alvin Peterson
The proton elastic form factors GEp(Q2) and GMp(Q2) have been extracted for Q2=1.75 to 8.83 (GeV/c)2 via a Rosenbluth separation to ep elastic cross section measurements in the angular range 13°≤θ≤90°. The Q2 range covered more than doubles that of the existing data. For Q2<4 >(GeV/c)2, where the data overlap with previous measurements, the total uncertainties have been reduced to < 14% in GEp and < 1.5% in GMp. Results for GEp(Q2) are consistent with the dipole fit GD(Q2)=(1+Q2/0.71)-2, while those for GMp(Q2)/μpGD(Q2) decrease smoothly from 1.05 to 0.92. Deviations from form factor scaling are observed up to 20%. The ratio Q2F2/F1 is observed to approach a constant value for Q2>3 (GeV/c)2. Comparisons are made to vector meson dominance, dimensional scaling, QCD sum rule, diquark, and constituent quark models, none of which fully characterize all the new data.
Interaction Of A Group Of Dislocations Within The Framework Of The Continuum Frenkel-Kontorova Model, Naum I. Gershenzon
Interaction Of A Group Of Dislocations Within The Framework Of The Continuum Frenkel-Kontorova Model, Naum I. Gershenzon
Physics Faculty Publications
The Frenkel-Kontorova (FK) model of edge dislocation is analyzed. Solutions of the continuum limit of the FK model [the sine-Gordon (SG) equation] are obtained in a form convenient for investigation of dynamics of a large number of interacting dislocations. We consider, based on these solutions, some nonstationary processes: dislocation generation, diffusion of dislocations, and crack-dislocation interaction. Simple relations connecting the velocity of plastic deformation, density and velocity of dislocations, and the force of interaction between dislocations are obtained. The nucleation of dislocations at a moving crack tip is described.
Comment On "Critical Behavior Of The Coulomb Glass", Thomas Vojta, Michael Schreiber
Comment On "Critical Behavior Of The Coulomb Glass", Thomas Vojta, Michael Schreiber
Physics Faculty Research & Creative Works
No abstract provided.
Anisotropy And Magneto-Optical Properties Of Sputtered Co/Ni Multilayer Thin Films, Y.B. Zhang, John A. Woollam, Z.S. Shan, J.X. Shen, David J. Sellmyer
Anisotropy And Magneto-Optical Properties Of Sputtered Co/Ni Multilayer Thin Films, Y.B. Zhang, John A. Woollam, Z.S. Shan, J.X. Shen, David J. Sellmyer
David Sellmyer Publications
Several series of sputtered Co/Ni multilayer thin films have been investigated. The volume and interface contributions to the magnetic anisotropy were determined from magnetization measurements, and the interface anisotropy, Ki= 0.23 ± 0.03 erg/cm2, was found to support perpendicular magnetic anisotropy. The anisotropy constant, K, increased with the Au buffer layer thickness, indicating the buffer layer was crucial to the perpendicular magnetic anisotropy. The polar Kerr rotation and coercivity as a function of temperature, and room temperature magneto-optical figure of merit are presented in this paper.
Binary-Encounter-Dipole Model For Electron-Impact Ionization, Yong-Ki Kim, M. Eugene Rudd
Binary-Encounter-Dipole Model For Electron-Impact Ionization, Yong-Ki Kim, M. Eugene Rudd
M. Eugene Rudd Publications
A theoretical model, which is free of adjustable or fitted parameters, for calculating electron impact ionization cross sections for atoms and molecules is presented. This model combines the binary-encounter theory with the dipole interaction of the Bethe theory for fast incident electrons. The ratios of the contributions from distant and close collisions and interference between the direct and exchange terms are determined by using the asymptotic behaviors predicted by the Bethe theory for ionization and for stopping cross sections. Our model prescribes procedures to calculate the singly differential cross section (energy distribution) for each subshell using the binding energy, average …
Nanostructures Of Sm-Co On Cr Thin Films, Yi Liu, B. W. Robertson, Z.S. Shan, S. Malhotra, M.J. Yu, S.K. Renukunta, Sy_Hwang Liou, David J. Sellmyer
Nanostructures Of Sm-Co On Cr Thin Films, Yi Liu, B. W. Robertson, Z.S. Shan, S. Malhotra, M.J. Yu, S.K. Renukunta, Sy_Hwang Liou, David J. Sellmyer
Sy-Hwang Liou Publications
The nanostructures of Sm-Co on Cr thin films prepared by dc magnetron sputtering were investigated by high resolution transmission electron microscopy (HRTEM) and diffraction techniques. HRTEM micrographs show that the crystallites in the Sm-Co films, as revealed by the lattice fringes, are distributed discontinuously in the matrix. The matrix is amorphous as indicated by the microdiffraction study. The size of the crystallites is in the range of 2~5 nanometers. The volume fraction of the crystallites in the film decreases from 91% to 54% as the argon pressure is increased from 5 mTorr to 30 mTorr. Micrographs recorded in a bright …
Quantum Manifestations Of Bifurcations Of Classical Orbits: An Exactly Solvable Mode, Aaron D. Peters, Charles Jaffé, John B. Delos
Quantum Manifestations Of Bifurcations Of Classical Orbits: An Exactly Solvable Mode, Aaron D. Peters, Charles Jaffé, John B. Delos
Arts & Sciences Articles
We examine photodetachment of H− in parallel electric and magnetic fields, hν+H−→H+e− using semiclassical approximations. The fields cause the electron to return to the atom, producing recurrences that are visible as interference oscillations in the photodetachment cross section. As the energy is varied, new returning orbits are created through bifurcations. Each such new recurrence increases the complexity of the absorption spectrum, and each bifurcation causes a local failure of the semiclassical approximation. The failure is repaired by a Fresnel diffraction integral.
Three-Body Analytical Potential For Interacting Helium Atoms, Carol A. Parish, Clifford E. Dykstra
Three-Body Analytical Potential For Interacting Helium Atoms, Carol A. Parish, Clifford E. Dykstra
Chemistry Faculty Publications
Large basis set ab initio calculations have been carried out for a dense grid of points on the He, potential energy surface. Three-body contributions were extracted at every point, and a number of concise functional representations for the three-body potential surface were then examined. Three-body multipolar dispersion terms and other radial and angular terms were used in the representations, and an assessment of relative importance of the different terms is presented. Combined with a two-body He-He potential, the results of this work should offer a high quality interaction potential for simulations of aggregated helium.
Cosmological And Wormhole Solutions In Low-Energy Effective String Theory, Mariano Cadoni, Marco Cavaglia
Cosmological And Wormhole Solutions In Low-Energy Effective String Theory, Mariano Cadoni, Marco Cavaglia
Physics Faculty Research & Creative Works
We derive and study a class of cosmological and wormhole solutions of low-energy effective string field theory. We consider a general four-dimensional string effective action where moduli of the compactified manifold and the electromagnetic field are present. The cosmological solutions of the two-dimensional effective theory obtained by dimensional reduction of the former are discussed. In particular we demonstrate that the two-dimensional theory possesses a scale-factor duality invariance. Eucidean four-dimensional instantons describing the nucleation of the baby universes are found and the probability amplitude for the nucleation process given.
A Magnetic, Neutron Diffraction, And Mössbauer Spectral Study Of The Nd₂Fe₁₇₋ₓalₓ Solid Solutions, Gary J. Long, Gaya Kanishka Marasinghe, Sanjay R. Mishra, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, D. P. Middleton, K. H. J. Buschow, Fernande Grandjean
A Magnetic, Neutron Diffraction, And Mössbauer Spectral Study Of The Nd₂Fe₁₇₋ₓalₓ Solid Solutions, Gary J. Long, Gaya Kanishka Marasinghe, Sanjay R. Mishra, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, D. P. Middleton, K. H. J. Buschow, Fernande Grandjean
Chemistry Faculty Research & Creative Works
The magnetic properties of a series of Nd2Fe17-xAlx solid solutions, with x equal to 2.04, 4.01, 5.97, 7.94, and 9.06, have been studied by magnetic measurements, neutron diffraction, and Mössbauer spectroscopy. Magnetization studies indicate that the Curie temperature increases from 330 K in Nd2Fe17 to a maximum of ~470 K at an x of 3.5. The compounds crystallize in the Th2Zn17 structure with lattice parameters and unit cell volumes which increase linearly with increasing aluminum content. The neutron diffraction results indicate that aluminum atoms are excluded from the 9d …
Neutron Diffraction And Mössbauer Effect Study Of Several Nd₂Fe₁₇₋ₓalₓ Solid Solutions, William B. Yelon, H. Xie, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow
Neutron Diffraction And Mössbauer Effect Study Of Several Nd₂Fe₁₇₋ₓalₓ Solid Solutions, William B. Yelon, H. Xie, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow
Physics Faculty Research & Creative Works
Aluminum-substituted Nd2Fe17-xAlx solid solutions with x=2.30, 4.44, 6.13, 8.00, and 9.40 have been studied by neutron diffraction and Mössbauer spectroscopy. A Rietveld analysis of the neutron scattering indicates that the aluminum atoms have a high initial affinity for the 18h site, show a high affinity for the 6c site at high aluminum concentrations, and are absent from the 9d site at all aluminum concentrations. The Mössbauer spectra show a maximum in both the maximum and weighted average hyperfine field for x≅2. This indicates that the lattice expansion which occurs with aluminum substitution is sufficient, at …
Driven Front And Interface Of A Fluid-Flow Model In 2+1-Dimensions, Michael J. Leaseburg, Ras B. Pandey
Driven Front And Interface Of A Fluid-Flow Model In 2+1-Dimensions, Michael J. Leaseburg, Ras B. Pandey
Faculty Publications
Computer simulations are performed to study the motion of the front and the growth of the interface width in a model of fluid flow driven by a biased field in 2+1 dimensions. The initial motion of the front is diffusive, which is followed by a nondiffusive power-law behavior in the long-time regime; the power-law exponent is nonuniversal, varying with the strength of the driven field. The growth of the interface width saturates in the asymptotic time regime. The saturated width W scales with both the driven field B as well as the transverse length L of the sample, leading to …
Mbe Growth Of Inxga1-Xas/Gaas/Si Heterostructure System, Jun Liu
Mbe Growth Of Inxga1-Xas/Gaas/Si Heterostructure System, Jun Liu
Theses
In this work, we grew the InxGa1-xAs/GaAs/Si (GaAs as buffer layer) by MBE technique. The surface of the buffer layer became microscopically rough as the thickness of the buffer layer increased and the growth mode of GaAs on Si underwent a change from three-dimensional to two-dimensional during the initial growth stage as indicated on the Reflection High Energy Electron Diffraction (RHEED) screen. The Scattering Electron Microscopy (SEM) observation of the etched surface of GaAs on Si showed that the structure of the buffer layer tended to be poly-crystalline and it was possible that a predominant orientation …
Measurement Of The Hall Coefficient And Electron Mobility Using Van Der Pauw Type Hall Effect Measurements, Hong-Sheng Luo
Measurement Of The Hall Coefficient And Electron Mobility Using Van Der Pauw Type Hall Effect Measurements, Hong-Sheng Luo
Theses
Hall effect measurement in the electrical characterization of semiconductor materials is very important. We set up the Hall effect measurement system and examined the system with a standard sample. The experimental results show that this Hall measurement system worked as well as expected. We also used this system to study the GaAs/GaAs and InGaAs/GaAs which grown by MBE. Finally, we disscussed and consided some common problems of Hall measurement. Some useful formulas and plots are presented.
Subthreshold Channel Leakage Current In Gaas Mesfet's, Wei Long
Subthreshold Channel Leakage Current In Gaas Mesfet's, Wei Long
Theses
In this thesis, a physical model including the subthreshold conpensation properties is presented. The Poisson equation is solved analytically in one dimension for GaAs MESFET's with undoped substrates in the subthreshold region. The solution is then used to derive expressions for subthreshold drain current and subshreshold swing in MESFET's with undoped substrates. Very good agreement between experimental and analytical results is achieved.
Two key parameters (Nilo and Iso) that determine the subthreshold Characteristics have been analyzed as a function of residual acceptor concentration Na, deep level EL2 concentration Nt, channel doping concentration Nd and threshold voltage Vt. It is shown …
Resonant Photoemission Studies Of Thickness Dependence Of The Unoccupied Gd 5d Bands, Peter A. Dowben, Dongqi Li, Jiandi Zhang, M. Onellion
Resonant Photoemission Studies Of Thickness Dependence Of The Unoccupied Gd 5d Bands, Peter A. Dowben, Dongqi Li, Jiandi Zhang, M. Onellion
Peter Dowben Publications
Ultrathin Gd films have been studied with constant initial-state spectroscopy (CIS) of photoemission utilizing linearly polarized light of synchrotron radiation. The photoemission cross-section of the 5d surface state near EF shows strong photon energy dependence, i.e., sharp peaks in CIS spectra near the Gd 5p1/2 adsorption edge. These peaks originate from resonant photoemission processes involving the occupied 5p and unoccupied 5d levels of the surface atoms. The symmetry of the unoccupied states were determined experimentally by changing the polarization of light, where p-polarized light excites only to the unoccupied dz2 or dxz,yz states and s-polarized light …
Particle Conjugation And The 1/N_C Corrections To G_A, Joseph Schechter, H. Weigel
Particle Conjugation And The 1/N_C Corrections To G_A, Joseph Schechter, H. Weigel
Physics - All Scholarship
We impose the requirement that the isovector axial vector current for the soliton sector of the chiral quark model transforms correctly under particle conjugation. This forces us to choose an otherwise arbitrary ordering of collective space operators in such a way that the next--to--leading 1/N_C correction to g_A vanishes.
On The Discretized Light Cone Quantization Of Electrodynamics, Alex C. Kalloniatis, David G. Robertson
On The Discretized Light Cone Quantization Of Electrodynamics, Alex C. Kalloniatis, David G. Robertson
Physics Faculty Scholarship
Discretized light-cone quantization of (3+1)-dimensional electrodynamics is discussed, with careful attention paid to the interplay between gauge choice and boundary conditions. In the zero longitudinal momentum sector of the theory a general gauge fixing is performed, and the corresponding relations that determine the zero modes of the gauge field are obtained. One particularly natural gauge choice in the zero mode sector is identified, for which the constraint relations are simplest and the fields may be taken to satisfy the usual canonical commutation relations. The constraints are solved in perturbation theory, and the Poincaré generators Pμ are constructed. The effect of …
Spontaneous Structure Formation In Driven Systems With Two Species: Exact Solutions In A Mean-Field Theory, I. Vilfan, R. K. P. Zia, Beate Schmittmann
Spontaneous Structure Formation In Driven Systems With Two Species: Exact Solutions In A Mean-Field Theory, I. Vilfan, R. K. P. Zia, Beate Schmittmann
Beate Schmittmann
A stochastic lattice gas of particles, subject to an excluded volume constraint and to a uniform external driving field, is investigated. Using a mean-field theory for a system with equal number of oppositely charged particles, exact results are obtained. Focusing on the current-vs-density plot, we propose an explanation for the discontinuous transition found in earlier simulations. A critical value of the drive, below which this transition becomes continuous, is found. These results are supported by a bifurcation analysis, leading to an equation of motion for the amplitude of the soft mode.