Electron in a Quantum Wire in the Presence of Parallel and Perpendicular Magnetic Fields

2013 ◽  
Vol 380-384 ◽  
pp. 4837-4840
Author(s):  
Xiu Zhi Duan ◽  
Guang Xin Wang
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Effective Mass ◽  
Electron Energy ◽  
Quantum Wire ◽  
Quantum Wires ◽  
Electron States ◽  
Mass Approximation ◽  
The Magnetic Field ◽  
Rectangular Quantum Wires

The electron states of self-assembled rectangular quantum wires (QWRs) are investigated in detail in the presence of a magnetic field. The calculations are done in the single band effective mass approximation. We study the electron states for the magnetic fields applied along and perpendicular to the wire, taking into account the different masses of the various particles inside and outside the QWRs. The electron energy and the influence of the magnetic field are discussed in this paper.

Magneto-Spectroscopy of Two-Electron Transitions in Homoepitaxial GaN.

2001 ◽  
Vol 693 ◽  
Author(s):  
M. Wojdak ◽  
J.M. Baranowski ◽  
A. Wysmolck ◽  
K. Pakula ◽  
R. Stepnicwski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Excited State ◽  
Magnetic Fields ◽  
Effective Mass ◽  
Electron Energy ◽  
Electron Transition ◽  
Electron Effective Mass ◽  
Neutral Donor ◽  
Electron Transitions ◽  
The Difference

AbstractTwo-electron transition occurs when the exciton bound to a neutral donor (DBE) recombines and leaves the donor in an excited state. The two-electron energy is therefore lower than that of the DBE peak by the difference in ground and excited state of the neutral donor. In a magnetic field the two-electron satellite splits into several components. These intra-donor excitations have been studied in homoepitaxial GaN up to magnetic fields reaching 23T. For Faraday (B‖c) configuration the two-electron transition splits mainly into 2s, 2p0, 2p+ and 2p- components. The total splitting between 2p+ and 2p- is equal to Landau energy. For Voigt (B???c) configuration in addition to transition to 2s, 2p0, 2p- and 2p+ there are additional lines which origin is discussed. It has been found that for two configurations of magnetic field the separation between 2p+ and 2p- is not exactly equal, what indicates the anisotropy of the electron effective mass. It has been found that m| = 0.205m0 and m??? = 0.225m0.

Electron Subband Levels of n-Type δ-Doped Quantum Wells under In-Plane Magnetic Fields

1997 ◽  
Vol 11 (09) ◽  
pp. 1195-1207
Author(s):  
E. K. Takahashi ◽  
A. T. Lino ◽  
L. M. R. Scolfaro
Keyword(s):  
Magnetic Field ◽  
Electronic Structure ◽  
Magnetic Fields ◽  
Quantum Well ◽  
Quantum Wells ◽  
Conduction Band ◽  
Electron Energy ◽  
Self Consistent ◽  
Plane Direction ◽  
The Magnetic Field

Self-consistent calculations of the electronic structure of center n-δ-doped GaAs/Al x Ga 1-x As quantum wells under in-plane magnetic fields are presented. The field B is varied up to 20 Tesla for different quantum well widths L w and sheet donor concentrations N D . The magnetic field produces noticeable changes in the energy dispersions along an in-plane direction perpendicular to B. The effects of B are more pronounced for higher electronic subbands. It is found that the diamagnetic shifts increase with increasing L w and/or N D . Contrarily to what has been observed in modulation-doped quantum wells, in these δ-doped systems the electron energy dispersions keep the single conduction band minimum at the center of the Brillouin zone even for intense magnetic fields.

THE EFFECT OF POSITION DEPENDENT EFFECTIVE MASS OF HYDROGENIC IMPURITIES IN PARABOLIC GaAs/GaAlAs QUANTUM DOTS IN A STRONG MAGNETIC FIELD

2009 ◽  
Vol 23 (26) ◽  
pp. 5109-5118 ◽  
Author(s):  
A. JOHN PETER
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Binding Energy ◽  
Effective Mass ◽  
Bound States ◽  
Mass Approximation ◽  
Infinite Case ◽  
Dependent Mass ◽  
The Magnetic Field ◽  
Peak Value

The binding energy of shallow hydrogenic impurities in parabolic GaAs/GaAlAs quantum dots is calculated as a function of dot radius in the influence of magnetic field. The binding energy has been calculated following a variational procedure within the effective-mass approximation. Calculations are presented with constant effective-mass and position dependent effective masses. A finite confining potential well with depth is determined by the discontinuity of the band gap in the quantum dot and the cladding. The results show that the impurity binding energy (i) increases as the dot radius decreases for the infinite case, (ii) reaches a peak value around 1R* as the dot radius decreases and then diminishes to a limiting value corresponding to the radius for which there are no bound states in the well for the infinite case, and (iii) increases with the magnetic field. Also it is found that (i) the use of constant effective mass (0.067 m0) is justified for dot sizes ≥ a* where a* is the effective Bohr radius which is about 100 Å for GaAs , in the estimation of ionization energy and (ii) the binding energy shows complicated behavior when the position dependent mass is included for the dot size ≤ a*. These results are compared with the available existing literatures.

Electron and Hole Levels in Rectangular Quantum Wires

2013 ◽  
Vol 380-384 ◽  
pp. 4833-4836
Author(s):  
Guang Xin Wang ◽  
Xiu Zhi Duan
Keyword(s):  
Magnetic Field ◽  
Ground State ◽  
State Energy ◽  
Quantum Wires ◽  
Excited State Energy ◽  
Mass Approximation ◽  
First Excited State ◽  
Diagonalization Method ◽  
The Wire ◽  
Rectangular Quantum Wires

Within the effective mass approximation and the diagonalization method, the problem of electron and hole levels in rectangular quantum wires (QWRs) is investigated in detail. The mismatch of material mass between the wire and the barrier and anisotropy of the hole mass is considered in our calculation. We study the ground-state energy and the first excited-state energy for the case of a magnetic field applied along the wire. The quantum behaviors are similar to that of other QWRs which were studied before.

SHAPE EFFECT OF SEMIMAGNETIC QUANTUM DOT ON THE BOUND MAGNETIC POLARON

2011 ◽  
Vol 10 (04n05) ◽  
pp. 665-668 ◽  
Author(s):  
A. MERWYN JASPER DE REUBEN ◽  
K. JAYAKUMAR
Keyword(s):  
Magnetic Field ◽  
Variational Principle ◽  
Binding Energy ◽  
Quantum Dot ◽  
Effective Mass ◽  
Shape Effect ◽  
Magnetic Polaron ◽  
Bound Magnetic Polaron ◽  
Mass Approximation ◽  
The Magnetic Field

The effect of geometry, concentration of Mn ion and the magnetic field on the binding energy of a donor and the donor bound magnetic polaronic shift in a finite Cd 1–x1 Mn x1 Te / Cd 1–x2 Mn x2 Te Quantum Dot within the effective mass approximation is carried out employing the variational principle. The results are presented and discussed.

ZEEMAN SPLITTING OF DONOR STATES IN GERMANIUM

1958 ◽  
Vol 36 (9) ◽  
pp. 1161-1167 ◽  
Author(s):  
R. R. Haering
Keyword(s):  
Magnetic Field ◽  
Effective Mass ◽  
Zeeman Effect ◽  
Zeeman Splitting ◽  
Energy Difference ◽  
Band Energy ◽  
Mass Approximation ◽  
Donor States ◽  
Energy Surfaces ◽  
The Magnetic Field

The linear Zeeman effect of the 2p m = ± 1 donor states is calculated in the effective mass approximation. The resulting level splitting is independent of the longitudinal mass characterizing the ellipsoidal conduction band energy surfaces. This result is valid as long as the Zeeman splitting of the m = ±1 states is small compared to the energy difference between the 2p m = 0 and the 2p m = ± 1 states. The Zeeman pattern to be expected in germanium is plotted as a function of the angle between the magnetic field and the (100) direction.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

scholarly journals An 84-μG Magnetic Field in a Galaxy at Z=0.692?

2008 ◽  
Vol 4 (S254) ◽  
pp. 95-96
Author(s):  
Arthur M. Wolfe ◽  
Regina A. Jorgenson ◽  
Timothy Robishaw ◽  
Carl Heiles ◽  
Jason X. Prochaska
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Faraday Rotation ◽  
Large Scale ◽  
Dynamo Model ◽  
Magnetic Field Generation ◽  
Interstellar Gas ◽  
Splitting Technique ◽  
Average Value ◽  
The Magnetic Field

AbstractThe magnetic field pervading our Galaxy is a crucial constituent of the interstellar medium: it mediates the dynamics of interstellar clouds, the energy density of cosmic rays, and the formation of stars (Beck 2005). The field associated with ionized interstellar gas has been determined through observations of pulsars in our Galaxy. Radio-frequency measurements of pulse dispersion and the rotation of the plane of linear polarization, i.e., Faraday rotation, yield an average value B ≈ 3 μG (Han et al. 2006). The possible detection of Faraday rotation of linearly polarized photons emitted by high-redshift quasars (Kronberg et al. 2008) suggests similar magnetic fields are present in foreground galaxies with redshifts z > 1. As Faraday rotation alone, however, determines neither the magnitude nor the redshift of the magnetic field, the strength of galactic magnetic fields at redshifts z > 0 remains uncertain.Here we report a measurement of a magnetic field of B ≈ 84 μG in a galaxy at z =0.692, using the same Zeeman-splitting technique that revealed an average value of B = 6 μG in the neutral interstellar gas of our Galaxy (Heiles et al. 2004). This is unexpected, as the leading theory of magnetic field generation, the mean-field dynamo model, predicts large-scale magnetic fields to be weaker in the past, rather than stronger (Parker 1970).The full text of this paper was published in Nature (Wolfe et al. 2008).

Magnetic Field Spectroheliograms from the San Fernando Observatory

1971 ◽  
Vol 43 ◽  
pp. 329-339 ◽  
Author(s):  
Dale Vrabec
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Spiral Structure ◽  
Longitudinal Component ◽  
Solar Telescope ◽  
Solar Magnetic Fields ◽  
San Fernando ◽  
Field Lines ◽  
The Magnetic Field ◽  
Field Network

Zeeman spectroheliograms of photospheric magnetic fields (longitudinal component) in the CaI 6102.7 Å line are being obtained with the new 61-cm vacuum solar telescope and spectroheliograph, using the Leighton technique. The structure of the magnetic field network appears identical to the bright photospheric network visible in the cores of many Fraunhofer lines and in CN spectroheliograms, with the exception that polarities are distinguished. This supports the evolving concept that solar magnetic fields outside of sunspots exist in small concentrations of essentially vertically oriented field, roughly clumped to form a network imbedded in the otherwise field-free photosphere. A timelapse spectroheliogram movie sequence spanning 6 hr revealed changes in the magnetic fields, including a systematic outward streaming of small magnetic knots of both polarities within annular areas surrounding several sunspots. The photospheric magnetic fields and a series of filtergrams taken at various wavelengths in the Hα profile starting in the far wing are intercompared in an effort to demonstrate that the dark strands of arch filament systems (AFS) and fibrils map magnetic field lines in the chromosphere. An example of an active region in which the magnetic fields assume a distinct spiral structure is presented.

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