scholarly journals Effect of a dc electric field on the longitudinal resistance of two-dimensional electrons in a magnetic field

2007 ◽  
Vol 75 (8) ◽  
Author(s):  
Jing-qiao Zhang ◽  
Sergey Vitkalov ◽  
A. A. Bykov ◽  
A. K. Kalagin ◽  
A. K. Bakarov
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Two Dimensional ◽  
Dc Electric Field ◽  
Longitudinal Resistance

RESONANT SPIN POLARIZATION IN A TWO-DIMENSIONAL HOLE GAS

2011 ◽  
Vol 25 (15) ◽  
pp. 1259-1270
Author(s):  
TIANXING MA
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Spin Polarization ◽  
Zeeman Splitting ◽  
Resonant Peak ◽  
Two Dimensional ◽  
Structural Inversion ◽  
Inversion Asymmetry ◽  
Peak Increase ◽  
Luttinger Hamiltonian

Within the Luttinger Hamiltonian, electric-field-induced resonant spin polarization of a two-dimensional hole gas in a perpendicular magnetic field was studied. The spin polarization arising from splitting between the light and the heavy hole bands shows a resonant peak at a certain magnetic field. Especially, the competition between the Luttinger term and the structural inversion asymmetry leads to a rich resonant peaks structure, and the required magnetic field for the resonance may be effectively reduced by enlarging the effective width of the quantum well. Furthermore, the Zeeman splitting tends to move the resonant spin polarization to a relative high magnetic field and destroy these rich resonant spin phenomena. Finally, both the height and the weight of the resonant peak increase as the temperature decreases. It is believed that such resonant spin phenomena may be verified in the sample of a two-dimensional hole gas, and it may provide an efficient way to control spin polarization by an external electric field.

scholarly journals Dielectric properties characterization of La- and Dy-doped BiFeO3 thin films

2007 ◽  
Vol 22 (8) ◽  
pp. 2179-2184 ◽  
Author(s):  
Peter Kr. Petrov ◽  
Vaijayanti R. Palkar ◽  
Alexander K Tagantsev ◽  
Hsin-I Chien ◽  
K. Prashanthi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Electric Field ◽  
Leakage Current ◽  
Structural Features ◽  
Type I ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Dc Electric Field ◽  
Measuring Frequency

The dielectric response of La- and Dy- doped BiFeO3 thin films at microwave frequencies (up to 12 GHz) has been monitored as a function of frequency, direct current (dc) electric field, and magnetic field in a temperature range from 25 to 300 °C. Both the real and imaginary parts of the response have been found to be non-monotonic (oscillating) functions of measuring frequency. These oscillations are not particularly sensitive to a dc electric field; however, they are substantially dampened by a magnetic field. The same effect has been observed when the volume of the characterized sample is increased. This phenomenon is attributed to the presence of a limited number of structural features with a resonance type response. The exact origin of these features is unknown at present. Leakage current investigations were performed on the whole set of films. The films were highly resistive with low leakage current, thereby giving us confidence in the microwave measurements. These typically revealed ‘N’-type I-V characteristics.

NON-LINEAR TRANSPORT IN VERY HIGH LANDAU LEVELS OF TWO-DIMENSIONAL ELECTRON SYSTEMS

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2684-2688 ◽  
Author(s):  
M. A. ZUDOV ◽  
H.-S. CHIANG ◽  
A. T. HATKE ◽  
W. ZHANG ◽  
L. N. PFEIFFER ◽  
...  
Keyword(s):  
Electric Field ◽  
High Mobility ◽  
Two Dimensional ◽  
Electron Systems ◽  
Dimensional Electron ◽  
Electron Transitions ◽  
Dc Electric Field ◽  
Phonon Absorption ◽  
Very High ◽  
Two Dimensional Electron Systems

We study magnetoresistivity oscillations induced by microwave radiation or acoustic phonons in high-mobility two-dimensional electron systems subject to dc electric field. In microwave-irradiated samples the response is governed by combined electron transitions, composed of microwave absorption and scattering off impurities. In non-irradiated samples, acoustic phonon resonances are tuned by dc electric field. Here, we show that in both experiments scattering off impurities without microwave or phonon absorption plays an important role and might even dominate the response.

NONLINEAR CURRENT DENSITY IN QUANTUM WELLS WITH PARABOLIC POTENTIAL UNDER CROSSED ELECTRIC AND MAGNETIC FIELDS

2012 ◽  
Vol 01 (02) ◽  
pp. 1250021
Author(s):  
BUI DINH HOI ◽  
TRAN CONG PHONG
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Quantum Wells ◽  
Effective Mass ◽  
Current Density ◽  
Electrical Transport ◽  
Physical Parameters ◽  
Electric And Magnetic Fields ◽  
Dc Electric Field

The DC electrical transport in a quantum well (QW) with parabolic confinement potential [Formula: see text] (where m and ωz are the effective mass of electron and the confinement frequency in z direction, respectively) subjected to a crossed DC electric field and magnetic field, is studied theoretically. The scattering by optical phonons is taken into account at high temperatures and strong magnetic fields. We obtained the expression for nonlinear current density (NCD) involving external (electric and magnetic) fields and characteristic parameters of QW. The dependence of NCD on the DC electric field is complicated. The analytical result is computationally evaluated and graphically plotted for a specific parabolic QW of GaAs / AlGaAs . The numerical results show the appearance of maximum peaks satisfying the condition of intersubband magnetophonon resonance (MPR) effect in the presence of a DC electric field. Especially, we show that the effect can be applied in experiment to determine some physical parameters by using magnetic field, such as the numbers of Landau levels for which electrons transfer, the effective mass, the charge of electrons or the confinement frequency characterized for PQW.

scholarly journals Effects of a Perpendicularly Applied Magnetic Field on Harmonically Driven Quasi-two-dimensional Electron Gas: the Static Macrostates Symmetry Breaking and Generation of Even Harmonics in System Output

2021 ◽  
Vol 17 (2) ◽  
pp. 141-156
Author(s):  
V. A. Smolar ◽  
◽  
T. I. Karyakina ◽  
I. I. Maglevanny ◽  
◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Internal Control ◽  
Order Parameter ◽  
High Harmonic ◽  
Two Dimensional ◽  
Control Parameters ◽  
Nonmonotonic Dependence ◽  
Cooperative Effects ◽  
Even Harmonics

In this paper, we consider activation processes in a nonlinear metastable system based on a quasi-two-dimensional superlattice and study the dynamics of such a system, which is externally driven by a harmonic force in regimes of controlled instabilities. The spontaneous transverse electric field is considered as an order parameter and the forced violations of the order parameter are considered as a response of a system to periodic driving. The internal control parameters are the longitudinal applied electric field, the sample temperature and the magnetic field which is orthogonal to the superlattice plane. We investigate the cooperative effects of self-organization and high harmonic forcing in such a system from the viewpoint of catastrophe theory It is shown through numerical simulations that the additional magnetic field breaks the static macrostates symmetry and leads to generation of even harmonics; it also allows the control of the intensity of particular harmonics. The intensity of even harmonics demonstrates resonant-type nonmonotonic dependence on control parameters with the maxima at points close to critical points of the synergetic potential.

scholarly journals High-efficiency acceleration by the combination of laser and electrostatic field

2014 ◽  
Vol 32 (4) ◽  
pp. 577-581 ◽  
Author(s):  
H. Lin ◽  
C.P. Liu ◽  
C. Wang ◽  
B.F. Shen
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Charged Particle ◽  
Electric Field ◽  
Laser Field ◽  
High Efficiency ◽  
Single Body ◽  
Body Dynamics ◽  
High Kinetic Energy ◽  
Dc Electric Field

AbstractA new scheme of particle acceleration is verified by the investigation on single-body dynamics of charged particle in a compound field setup. This compound field setup contains a linear polarized laser field and a DC electric field which is along the direction of laser magnetic field. This setup can cause a charged particle to be of aperiodic motion and significantly high kinetic energy. Moreover, the contribution from the motion vertical to accelerating electric field is fully taken into account and is found to be essential to efficient acceleration. The efficiency of such a setup in acceleration is higher than that of a single laser.

Magnetometric resistivity (MMR) anomalies of two‐dimensional structures

Geophysics ◽  
1979 ◽  
Vol 44 (5) ◽  
pp. 947-958 ◽  
Author(s):  
E. Gomez Trevino ◽  
R. N. Edwards
Keyword(s):  
Magnetic Field ◽  
Integral Equation ◽  
Fourier Transform ◽  
Electric Field ◽  
Current Source ◽  
Two Dimensional ◽  
Galvanic Current ◽  
One Dimensional ◽  
The Magnetic Field ◽  
Surface Integrals

An inexpensive, rapid method has been developed for computing all three components of the magnetic field due to galvanic current flow from a point electrode in the vicinity of a conductive subsurface structure of infinite strike‐length and arbitrary cross‐section. For any three‐dimensional (3-D) structure, the magnetic field may be written as a sum of surface integrals over boundaries defining changes in conductivity by a direct modification of the Biot‐Savart law. The integrand of each surface integral includes the components of the electric field tangential to the boundary, which may be evaluated on the boundary using a standard integral equation technique. In the case of a two‐dimensional (2-D) structure, a reformulation of the theory by taking a one‐dimensional Fourier transform along the strike results in the reduction of both the surface integrals necessary to solve the integral equation for the electric field, and the integrals used in computing the magnetic field, to line integrals in wavenumber domain. We evaluate the integrals numerically and solve the integral equation for each of about ten wavenumbers; finally, we obtain the magnetic field in space domain through a concluding one‐dimensional inverse Fourier transform. Type curves and characteristic curves for the simple model of a buried horizontal cylinder beneath a thin layer of conductive overburden are constructed. In the absence of overburden, the half‐width of the anomaly is linearly related to the depth of the cylinder. In the presence of overburden, the form of the anomaly may be predicted in a simple manner from the corresponding anomaly in the absence of overburden, provided the distance from the current source is sufficiently large for most of the available current to have penetrated the overburden.

A Magnetoelectric Effect in Low-Carrier Density Colossal Magnetoresistance Materials

2006 ◽  
Vol 52 ◽  
pp. 21-26
Author(s):  
M. Auslender
Keyword(s):  
Magnetic Field ◽  
Solid State ◽  
Electric Field ◽  
Acoustic Waves ◽  
Carrier Density ◽  
Colossal Magnetoresistance ◽  
Magnetoelectric Effect ◽  
Strong Electric Field ◽  
Acoustoelectric Effect ◽  
Dc Electric Field

It is shown that in colossal magnetoresistance materials an inhomogeneous alternating magnetic field generates a strong electric field of non-inductive nature. This magnetoelectric effect is an analog of acoustoelectric effect in conventional semiconductors. Due to the above electric field spin waves in the former materials, like acoustic waves in the latter ones, acquire an additional attenuation at equilibrium. This attenuation may be converted to amplification by applying strong enough dc electric field drifting the carriers (solid-state Cherenkov’s effect). The experiments, which probed this phenomenon in HgCr2Se4 using spin wave pumping, are discussed.

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