Electric field charging

The authors use optical spectroscopy of gate-induced charge carriers to show that, at low temperature and small lateral electric field, charges become localized onto individual molecules in shallow trap states, but that at moderate temperatures an electric field is able to detrap them, resulting in transport that is not temperature-activated. This work demonstrates that transport in such systems can be interpreted in terms of classical semiconductor physics and there is no need to invoke onedimensional Luttinger liquid physics [168]. 

The term piezoelectric nonlinearity is used here to describe relationship between mechanical and electrical fields (charge density D vs. stress a, strain x vs. electric field E) in which the proportionality constant d, is dependent on the driving field, Figure 13.1. Thus, for the direct piezoelectric effect one may write D = d(a)a and for the converse effect x = d(E)E. Similar relationships may be defined for other piezoelectric coefficients (g, h, and e) and combination of electro-mechanical variables. The piezoelectric nonlinearity is usually accompanied by the electro-mechanical (D vs. a or x vs. E) hysteresis, as shown in Figure 13.2. By hysteresis we shall simply mean, in the first approximation, that there is a phase lag between the driving field and the response. This phase lag may be accompanied by complex nonlinear processes leading to a more general definition of the hysteresis [2],... 

Effect of Electric Fields. Charge-ordered manganates such as Pri -tCa,Mn03 (x 0.3—0.4) undergo a CO-FMM transition... 

Anderson (1992) and Davis (1992) have noted that because all ER fluids have some electrical conductivity, then for direct current (dc) or slow alternating current (ac) electric fields, charges will migrate to the particles, eventually completely screening out the dipoles within the particles. If the electrical conductivity of the medium,, differs from that of the particles, Up, then there will still be an effective particle polarizability but its magnitude... 

We have developed an unified adiabatic approach allowing one to tackle transport problems in traps of different geometry. The magnetic and electrical fields, charge screening, and other factors (a spin-orbit interaction, hyperfine structure, etc) can influence the quantum dot paths within an easily tractable Breit-Wigner-resonance approximation for the electron scattering. The utility... 

The typical decay hme for the relaxahon of nonporated vesicles, t, is of the order of 100 ps. It is set by the relaxahon of the membrane tension achieved at the end of the pulse. The membrane tension, acquired during the pulse, also referred to as electric tension, arises from the transmembrane potenhal, ( , built across the membrane during the pulse. Lipid membranes are impermeable to ions and, in the presence of an electric field, charges accumulate on both sides of the bilayer, which gives rise to this transmembrane potential [91] ... 

When an insulating material is subjected to an applied electric field, charge separation and molecular rearrangement occur within the material, causing the phenomenon of polarization. The magnitude of the polarization is measured by a property of the material called the dielectric constant. This macroscopic... 

A three-dimensional time-dependent model has been developed by Ma et al. (1998) to solve for the electric field, charge density, and Maxwell current. The last quantity is influenced primarily by the spatially anisotropic tensor conductivity in the ionosphere. Maxwell s equations for the transient fields propagating into the ionosphere are reduced to two equations. If p is the charge density (C/m ), q the dielectric constant (C /N m ), the permeability (N/A ), 0 the conductivity tensor (S/m), and E the electric field (V/m), then the wave equation in SI imits becomes... 

If a conductor is placed in an electric field, charges will move within the conductor until the interior field is zero. In the case of an insulator, no free charges exist, so net migration of charge does not occur. In polar materials, however, the positive and negative charge centers in the molecules do not coincide. An electric dipole moment, p, is said to exist. An applied field, E, tends to orient the dipoles and produces a field inside the dielectric, Ep, which opposes the applied field. This process is called polarization. Most materials contain a combination of orientable dipoles and relatively free charges so that... 

Hoburg and Melcher [6] demonstrated electrohydrodynamic instabilities in macroscale systems at an oil-oil interface with a discrete conductivity change at the interface under the influence of an applied electric field. In the presence of an applied electric field, charge accumulates at the fluid-fluid interface, and the electrical force on the interface is balanced by the fluid interfacial stress tensor. At a critical field strength, the electrical force exceeds the... 

By interaction with DC electric fields, charged biomolecules can be directly transported using electrophoresis. Assuming a charged, spherical particle of radius R that is surroimded by a counterion shell of thickness lo, both the inner sphere of radius R and the outer one of radius R + Ij are subjected to oppositely directed forces in the external field. In equilibrium, this force is equal to the friction force in the liquid, according to Stokes law. The net velocity of the particle moving together with its double layer results from the sum of both contributions and can be calculated to [2]... 

Electrostatic forces are interactions between static electric fields charge distributions. 

Although the low electric field percolation model is useful in organic field effect transistors, it is not suitable for OLEDs or OPVs due to the much larger electric fields in these devices. Under an applied electric field, charge carriers hop from sites deep in the DOS to higher energy levels where the DOS is broader (see Fig. 1). The effect of the electric field is fo create a population of hot carriers above the Fermi level [18]. The aim of the effective temperature concept is to model the electric field by a nonequilibrium disfribution of elecfrons characterized by an effective temperature Teff. 

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