Search results for "INTERFACE"
showing 10 items of 2139 documents
Attractive ion-ion correlation forces and the dielectric approximation.
2016
We analyze the classical problem of the interaction between two charged surfaces separated by a solution containing neutralizing counter-ions. The focus is on obtaining a description where the solvent is treated explicitly rather than through a dielectric approximation as is conventionally done. We summarize the results of three papers where we have used a Stockmayer fluid model in Monte Carlo simulations. It is shown that the attractive ion-ion correlation mechanism is also operating when the solvent is described explicitly. There appears an oscillatory component to the force, but when this is accounted for, there is a semi-quantitative agreement between the continuum model and the model w…
An extrinsic interface developed in an equilibrium based finite element formulation
2019
Abstract The phenomenon of delamination in composite material is studied in the framework of hybrid equilibrium based formulation with extrinsic cohesive zone model. The hybrid equilibrium formulation is a stress based approaches defined in the class of statically admissible solutions. The formulation is based on the nine-node triangular element with quadratic stress field which implicitly satisfy the homogeneous equilibrium equations. The inter-element equilibrium condition and the boundary equilibrium condition are imposed by considering independent side displacement fields as interfacial Lagrangian variable, in a classical hybrid formulation. The hybrid equilibrium element formulation is…
Gaussian quantum dots of type II in in-plane electric field
2007
The growing interest is recently focusing on QDs of type II, which contrary to type I QDs attract electrons and repulse holes (or conversely). In such QDs an electron-hole pair (Xexciton) can still be traped due to electron-hole Coulomb attraction, resulting in significantly more complex structure of excitonic states. We consider an X exciton in QD of type II defined by electrostatic focusing in a narrow quantum well, in the presence of additional external in-plane electric field. The dependence of PL spectrum on dot size and in-plane electric field is analysed within the Hartree approach for model planar Gaussian confinement. The exciton ground state and its energy red-shift are found as a…
The Ising model as a playground for the study of wetting and interface behavior
2000
Computer simulations have played an important role in the elucidation of wetting and interface unbinding phenomena. In particular, use of the Ising-lattice-gas model in a film geometry and subject to diverse surface and bulk magnetic fields has permitted extensive Monte Carlo simulations to reveal new features of the phase diagrams associated with these phenomena and to provoke new theoretical studies. The status of our knowledge about the nature of wetting and interface-delocalization transitions which has resulted from these Ising model simulations will be summarized.
Laser action in electrically driven quantum dot matrix
2007
A lasing system based on electrically driven quantum dot matrix is proposed, where population inversion of the dot matrix is obtained by rapid (nonadiabatic) switching on of in-plane electric field as a pumping force. Numerical analysis of electron-photon system kinetics is performed for various electric fields and temperatures. For parabolic type of confinement in QDs, a convenient amplification of contribution from several levels is indicated. The relevant analysis utilises an exact solution of Cauchy problem for an infinite chain of linear differential equations.
Orbital origin and matrix element effects in the Ag/Si(111)-()R30° Fermi surface
2007
The Fermi surface (FS) of the Ag/Si(1 1 1)-3×3 reconstruction with an excess of Ag has been mapped by angle resolved photoemission spectroscopy with polarized light in a wide region of the reciprocal space and with different detection geometries. In contrast to previous results, a strong polarization dependence is observed. Applying the dipole selection rules, it is found that the surface state at the Fermi level, S1 state, has odd symmetry with respect to the mirror plane of the honeycomb-chained triangle structure, indicating that it is mainly derived from Ag 5px and 5py orbitals. This conclusion is revised in the new frame of a inequivalent-triangle structure for the Ag/Si(1 1 1)-3×3 at …
Properties of the Ising magnet confined in a corner geometry
2007
Abstract The properties of Ising square lattices with nearest neighbor ferromagnetic exchange confined in a corner geometry, are studied by means of Monte Carlo simulations. Free boundary conditions at which boundary magnetic fields ± h are applied, i.e., at the two boundary rows ending at the lower left corner a field + h acts, while at the two boundary rows ending at the upper right corner a field − h acts. For temperatures T less than the critical temperature T c of the bulk, this boundary condition leads to the formation of two domains with opposite orientation of the magnetization direction, separated by an interface which for T larger than the filling transition temperature T f ( h ) …
Search for new physics using QUAERO: A general interface to D0 Event data
2001
We describe Quaero, a method that i) enables the automatic optimization of searches for physics beyond the standard model, and ii) provides a mechanism for making high energy collider data generally available. We apply Quaero to searches for standard model WW, ZZ, and ttbar production, and to searches for these objects produced through a new heavy resonance. Through this interface, we make three data sets collected by the D0 experiment at sqrt(s)=1.8 TeV publicly available.
Laser-driven quantum magnonics and terahertz dynamics of the order parameter in antiferromagnets
2017
The impulsive generation of two-magnon modes in antiferromagnets by femtosecond optical pulses, so-called femto-nanomagnons, leads to coherent longitudinal oscillations of the antiferromagnetic order parameter that cannot be described by a thermodynamic Landau-Lifshitz approach. We argue that this dynamics is triggered as a result of a laser-induced modification of the exchange interaction. In order to describe the oscillations we have formulated a quantum mechanical description in terms of magnon pair operators and coherent states. Such an approach allowed us to} derive an effective macroscopic equation of motion for the temporal evolution of the antiferromagnetic order parameter. An impli…
Cluster growth with long-range interactions
1996
Abstract Growth models in which the morphology depends on interactions of the type V(r) = C r n are presented. The growth algorithms are generalizations of DLA. The particles diffuse on a triangular lattice and eventually either stick to the cluster or are lost. Several processes are simulated in this way: in one case only pure sticking is taken into account, in another case evaporation and rearrangement are also allowed to occur. In the former case (with attractive interactions) the clusters exhibit a highly symmetric shape (a sixfold star) whose detailed structure depends on n , C kT , and time. In the latter case (studied with repulsive dipolar interactions) the tendency to ramification …