DIFFERENTIAL RESISTANCE OF TWO DIMENSIONAL ELECTRON SYSTEMS SUBJECT TO MICROWAVE RADIATION

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2693-2697 ◽  
Author(s):  
MAXIM KHODAS ◽  
MAXIM G. VAVILOV
Keyword(s):  
Electric Field ◽  
Microwave Radiation ◽  
Electric Fields ◽  
Constant Electric Field ◽  
Electron Distribution Function ◽  
Differential Resistance ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Scattering Rate ◽  
Strong Electric Fields

We present the expression for differential resistance of a disordered two-dimensional electron gas placed in a perpendicular magnetic field and subject to microwave irradiation. We demonstrate that in strong dc electric fields the current oscillates as a function of the strength of the applied constant electric field. We demonstrate that the amplitude of oscillations of the differential resistivity is characterized by the back-scattering rate off disorder. We argue that the dominant contribution to the non-linearity in strong electric fields originates from the modification of electron scattering off disorder by electric fields, or so-called "displacement" mechanism. The non-equilibrium mechanism, which is related to modification of electron distribution function by electric fields turns out to be inefficient in strong electric fields, although it describes current in weak electric fields. We further analyze the positions of maxima and minima of the differential resistance as a function of the applied electric field and frequency of microwave radiation.

scholarly journals Currents of created pairs in strong electric fields

2021 ◽  
pp. 2150134
Author(s):  
E. T. Akhmedov ◽  
A. V. Anokhin ◽  
D. I. Sadekov
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Constant Electric Field ◽  
Tree Level ◽  
Two Dimensional ◽  
Klein Paradox ◽  
Strong Electric Fields ◽  
Initial States ◽  
Thermal States

In this paper, we calculate tree-level currents of created particles in strong background electric fields in 4D QED for various initial states. Namely, we do that in pulse background for initial vacuum and thermal states at past infinity. In both cases, we find that the current grows linearly with the length of the pulse with coefficients of proportionality containing the characteristic Schwinger’s factor. For the constant electric field background, we calculate the current for several different initial states. We observe that in such a case the current is either zero or linearly divergent. We explain the reason for such a behavior and compare the situation in ordinary and scalar QED. Finally, we calculate the current in two-dimensional situation in the presence of such settings when the so-called Klein paradox can be observed.

Resonant detection of microwave radiation in a circular two-dimensional electron system with quantum point contacts

2005 ◽  
Vol 87 (9) ◽  
pp. 092107 ◽  
Author(s):  
P. S. Dorozhkin ◽  
S. V. Tovstonog ◽  
S. A. Mikhailov ◽  
I. V. Kukushkin ◽  
J. H. Smet ◽  
...  
Keyword(s):  
Microwave Radiation ◽  
Electron System ◽  
Quantum Point Contacts ◽  
Two Dimensional ◽  
Point Contacts ◽  
Dimensional Electron ◽  
Dimensional Electron System ◽  
Quantum Point

Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

2009 ◽  
Vol 626 ◽  
pp. 367-393 ◽  
Author(s):  
STEFAN MÄHLMANN ◽  
DEMETRIOS T. PAPAGEORGIOU
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Electric Field ◽  
Electric Fields ◽  
Simple Shear ◽  
Simple Shear Flow ◽  
Physical Parameters ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

Effects of DC electric fields on neuronal excitability: A bifurcation analysis

2014 ◽  
Vol 28 (18) ◽  
pp. 1450114 ◽  
Author(s):  
Yanqiu Che ◽  
Huiyan Li ◽  
Chunxiao Han ◽  
Xile Wei ◽  
Bin Deng ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Parameter Space ◽  
Bifurcation Analysis ◽  
Neural Control ◽  
Neuronal Excitability ◽  
Modulation Method ◽  
Two Dimensional ◽  
Dimensional Parameter ◽  
Dc Electric Fields

In this paper, the effects of external DC electric fields on the neuro-computational properties are investigated in the context of Morris–Lecar (ML) model with bifurcation analysis. We obtain the detailed bifurcation diagram in two-dimensional parameter space of externally applied DC current and trans-membrane potential induced by external DC electric field. The bifurcation sets partition the two-dimensional parameter space in terms of the qualitatively different behaviors of the ML model. Thus the neuron's information encodes the stimulus information, and vice versa, which is significant in neural control. Furthermore, we identify the electric field as a key parameter to control the transitions among four different excitability and spiking properties, which facilitates the design of electric fields based neuronal modulation method.

Sign in / Sign up

Export Citation Format

Share Document