scholarly journals Quantum effects in magnetotransport of InGaAs quantum wells with remote Mn impurities

2018 ◽  
Vol 185 ◽  
pp. 06007
Author(s):  
Leonid Oveshnikov ◽  
Leonid Morgun ◽  
Elena Nekhaeva ◽  
Vladimir Kulbachinskii ◽  
Boris Aronzon
Keyword(s):  
Magnetic Field ◽  
Quantum Wells ◽  
Hall Effect ◽  
Quantum Corrections ◽  
Magnetic Impurities ◽  
Magnetic Subsystem ◽  
Magnetic Structures ◽  
Conduction Channel ◽  
Shubnikov De Haas Oscillations ◽  
The Impact

We have studied magnetoresistance and Hall effect of GaAs/InxGa1−xAs quantum wells with remote Mn impurity. Temperature and magnetic field dependencies of samples resistivity indicate several effects related to the magnetic subsystem. Shubnikov - de Haas oscillations indicate the presence of several types of regions in conduction channel with significantly different hole mobilities. We discussed the impact of magnetic impurities on quantum corrections to conductivity by comparing our results with the data for similar non-magnetic structures. Our results suggest that the presence of Mn atoms leads to the damping of quantum corrections in in the investigated structures.

The impact of non-ideal effects on the circumstellar disk evolution and their observational signatures

2018 ◽  
Vol 14 (A30) ◽  
pp. 116-116
Author(s):  
Y. Tsukamoto ◽  
S. Okuzumi ◽  
K. Iwasaki ◽  
M. N. Machida ◽  
S. Inutsuka
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Recent Observation ◽  
Ambipolar Diffusion ◽  
Circumstellar Disk ◽  
Neutral Drift ◽  
Disk Formation ◽  
Evolutionary Phase ◽  
The Impact ◽  
The Magnetic Field

AbstractIt has been recognized that non-ideal MHD effects (Ohmic diffusion, Hall effect, ambipolar diffusion) play crucial roles for the circumstellar disk formation and evolution. Ohmic and ambipolar diffusion decouple the gas and the magnetic field, and significantly reduces the magnetic torque in the disk, which enables the formation of the circumstellar disk (e.g., Tsukamoto et al. 2015b). They set an upper limit to the magnetic field strength of ∼ 0.1 G around the disk (Masson et al. 2016). The Hall effect notably changes the magnetic torques in the envelope around the disk, and strengthens or weakens the magnetic braking depending on the relative orientation of magnetic field and angular momentum. This suggests that the bimodal evolution of the disk size possibly occurs in the early disk evolutionary phase (Tsukamoto et al. 2015a, Tsukamoto et al. 2017). Hall effect and ambipolar diffusion imprint the possibly observable characteristic velocity structures in the envelope of Class 0/I YSOs. Hall effect forms a counter-rotating envelope around the disk. Our simulations show that counter rotating envelope has the size of 100–1000 au and a recent observation actually infers such a structure (Takakuwaet al. 2018). Ambipolar diffusion causes the significant ion-neutral drift in the envelopes. Our simulations show that the drift velocity of ion could become 100-1000 ms–1.

scholarly journals MAGNETOTRANSPORT IN DILUTE 2D SI-MOSFET SYSTEM

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3609-3612 ◽  
Author(s):  
M. V. CHEREMISIN
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Field Configuration ◽  
Zero Field ◽  
Magnetic Field Configuration ◽  
Valley Splitting ◽  
2D System ◽  
Shubnikov De Haas Oscillations

The beating pattern of Shubnikov-de Haas oscillations is reproduced in crossed magnetic field configuration and in presence of zero-field valley splitting in Si -MOSFET 2D system. The features of Quantum Hall Effect in extremely dilute 2D system are discussed.

scholarly journals A porcupine Sun? Implications for the solar wind and Earth

2011 ◽  
Vol 7 (S286) ◽  
pp. 210-214 ◽  
Author(s):  
Sarah E. Gibson ◽  
Liang Zhao
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Spatial Scales ◽  
Coronal Magnetic Field ◽  
Heliospheric Current Sheet ◽  
Magnetic Structures ◽  
Fast Wind ◽  
Global Configuration ◽  
Slow Wind ◽  
The Impact

AbstractThe recent minimum was unusually long, and it was not just the case of the “usual story” slowed down. The coronal magnetic field never became completely dipolar as in recent Space Age minima, but rather gradually evolved into an (essentially axisymmetric) global configuration possessing mixed open and closed magnetic structures at many latitudes. In the process, the impact of the solar wind at the Earth went from resembling that from a sequence of rotating “fire-hoses” to what might be expected from a weak, omnidirectional “lawn-sprinkler”. The previous (1996) solar minimum was a more classic dipolar configuration, and was characterized by slow wind of hot origin localized to the heliospheric current sheet, and fast wind of cold origin emitted from polar holes, but filling most of the heliosphere. In contrast, the more recent minimum solar wind possessed a broad range of speeds and source temperatures (although cooler overall than the prior minimum). We discuss possible connections between these observations and the near-radial expansion and small spatial scales characteristic of the recent minimum's porcupine-like magnetic field.

Quantum Hall Effect in AlGaAs and Graphite Quantum Dots

2013 ◽  
Vol 667 ◽  
pp. 1-9 ◽  
Author(s):  
Keshav N. Shrivastava
Keyword(s):  
Magnetic Field ◽  
Quantum Wells ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Two Dimensional ◽  
Hall Resistivity ◽  
Angular Momenta ◽  
The Difference ◽  
Density Of Electrons

Abstract. The 30 nm wide quantum wells on a 4x4 mm2 piece of GaAs/AlGaAs are formed when the layers of GaAs are deposited on AlGaAs films. The two-dimensional density of electrons is 3x1011 cm-2 and the mobility is 32x106 cm2/Vs. In such a sample the Hall resistivity as a function of magnetic field is not a linear function. Hence a suitable theory to understand the Hall effect is formulated. We find that there are phase transitions as a function of temperature. There are lots of fractions of charge which are explained on the basis of spin and orbital angular momentum of the electron. The nano meter size films of graphite also show that the Hall resistivity is non-linear and shows steps as a function of magnetic field. We make an effort to understand the steps in the Hall effect resistivity of graphite with quantum wells formed on the surface. It is found that the fractions are in four categories, (i) the principal fractions which are determined by spin and orbital angular momenta, (ii) the resonances which occur at the difference between two values such as =1-2, (iii) two-particle states which occur at the sum of the two frequencies and (iv) there are clusters of electrons localized in some areas of the sample. The spin in the clusters is polarized so that it becomes NS which is not 1/2 but depends on the number N, of electrons in a cluster.

scholarly journals Oscillations of the degree of circular polarization in the optical spin Hall effect

2018 ◽  
Vol 60 (8) ◽  
pp. 1582
Author(s):  
D. Schmidt ◽  
B. Berger ◽  
M. Bayer ◽  
C. Schneider ◽  
S. Hofling ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Wells ◽  
Hall Effect ◽  
Momentum Space ◽  
Spin Hall Effect ◽  
Effective Magnetic Field ◽  
Exciton Polaritons ◽  
Semiconductor Microcavities ◽  
Space Dynamics ◽  
Good Agreement

AbstractThe optical spin Hall effect appears when elastically scattered exciton polaritons couple to an effective magnetic field inside of quantum wells in semiconductor microcavities. Theory predicts an oscillation of the pseudospin of the exciton polaritons in time. Here, we present a detailed analysis of momentum space dynamics of the exciton polariton pseudospin. Compared to what is predicted by theory, we find a higher modulation of the temporal oscillations of the pseudospin. We attribute the higher modulation to additional components of the effective magnetic field which have been neglected in the foundational theory of the optical spin Hall effect. Adjusting the model by adding non-linear polariton-polariton interactions, we find a good agreement in between the experimental results and simulations.

Influences on Occurrence of Magnetism During Cutting Processes

2011 ◽  
Vol 5 (3) ◽  
pp. 294-299
Author(s):  
Dirk Bähre ◽  
◽  
Kirsten Trapp ◽  
Ralf Tschuncky ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Hall Effect ◽  
Ferromagnetic Materials ◽  
Material Structure ◽  
Time Dependency ◽  
Technological Parameters ◽  
Cutting Processes ◽  
The Impact ◽  
The Magnetic Field

Workpieces from ferromagnetic materials influenced by machining can build magnetic fields, which can cause problems in production or application. One of the assumed causes of magnetism occurring in cutting processes is the change in the material structure due to the impact of the tool. To study these influences, milling tests are carried out. The magnetic field is measured by means of sensors functioning on the basis of the Hall effect. The coherences between geometry, kinematics, technological parameters, time dependency, and the magnetisation characteristics of the workpiece are considered.

scholarly journals COULOMB DRAG IN DOUBLE QUANTUM WELLS WITH A PERPENDICULAR MAGNETIC FIELD

1996 ◽  
Vol 10 (07) ◽  
pp. 279-285 ◽  
Author(s):  
M.W. WU ◽  
H.L. CUI ◽  
N.J.M. HORING
Keyword(s):  
Magnetic Field ◽  
Quantum Wells ◽  
Momentum Transfer ◽  
Electron Interaction ◽  
Double Quantum ◽  
Perpendicular Magnetic Field ◽  
Drag Effect ◽  
Coulomb Drag ◽  
Shubnikov De Haas Oscillations ◽  
The Magnetic Field

Momentum transfer due to electron–electron interaction (Coulomb drag) between two quantum wells, separated by a distance d, in the presence of a perpendicular magnetic field, is studied at low temperatures. We find besides the well known Shubnikov-de Haas oscillations, which also appear in the drag effect, the momentum transfer is markedly enhanced by the magnetic field.

Sign in / Sign up

Export Citation Format

Share Document