Kane Model Research Articles

Electron Lande g-factor in GaAs/Al xGa 1−xAs quantum wires

Energy spectrum of charge carriers is researched with and without magnetic field in Kane-type semiconductor quantum nanostructures in case of finite potential barrier V. The model that is considered in the present study is composed of two concentric quantum wires. The inner part and outer part are made up of GaAs and Al x Ga 1− x As, respectively. In the first part, it is shown that energy spectrum of carriers depends on quantum wire radius for finite potential barrier without magnetic field by using Kane model. In the second part, energy spectra of charge carriers are calculated as the function of magnetic field by using Kane model in Al x Ga 1− x As/GaAs quantum wire and compared with results of parabolic approach. It is also shown that g-factors of electrons rely on radius. It is seen that g-factor of electrons is increasing while radius is decreasing. The applied model is also useful for obtaining the energy spectra of light holes and spin–orbit splitting holes.

Interband transition in narrow gap InSb spherical layer quantum dot in the presence of electric field

We perform the theoretical investigation of interband dipole transitions in a narrow- gap InSb spherical layer quantum dot. We consider the transitions from the light hole and heavy hole states to the electron state of the conduction band. The dispersion law for electron and light hole is approximated using a two-band Kane model, while the heavy hole is described in the parabolic approximation. The effect of electric field on interband transitions is investigated.

Effect of a phase transition on the electron energy spectrum in Ag2S

Temperature dependences of electrical conductivity σ, Hall coefficient R, and thermopower α0 in Ag2S are reported. It is established that at T ≈ 435 ± 5 K, all kinetic parameters vary drastically, which is associated with a change in parameters of the conduction band. It is shown that the dispersion law of electron energy in β-Ag2S corresponds to the Kane model.

The Impact of State Ownership on Performance Differences in Privately-Owned Versus State-Owned Banks: An International Comparison

This paper employs cash flow and accounting based measures to examine performance differences between privately-owned and state-owned banks in sixteen Far East countries from 1989 through 2004, a period including the 1997 Asian financial crisis. We find that state-owned banks operated less profitably, held less core capital, and had greater credit risk than privately-owned banks prior to 2001, and the performance differences are more significant in those countries with greater government involvement and political corruption in the banking system. In addition, from 1997 to 2000, the 4-year period after the beginning of the Asian financial crisis, the deterioration in the cash flow returns, core capital and credit quality of state-owned banks was significantly greater than that of privately-owned banks, and the contrast between the two types of banks during this period is especially sharp for the countries that were hardest hit by the Asian crisis. We also find that state-owned banks finance the government to a greater degree than do privately-owned banks in countries where the government is involved heavily in the banking system. However, state-owned banks closed the gap with privately-owned banks on cash flow returns, core capital, and nonperforming loans in the post-crisis period of 2001-2004. Taken together, our findings can best be explained by Shleifer and Vishny's (1997) corporate governance theory on government ownership of banks and Kane's (2000) life-cycle model of a regulation-induced banking crisis.

Band gap narrowing and radiative efficiency of silicon doped GaN

Radiative efficiency, band gap narrowing, and band filling are studied in Si-doped GaN films as a function of carrier concentration (n), using room and low temperature cathodoluminescence (CL). Using the Kane model, a band gap narrowing ΔEg of −(3.6±0.6)×10−8 and −(2.6±0.6)×10−8n1/3 eVn1/3 is obtained for epitaxially strained and relaxed material, respectively. Band-edge CL time response and absolute external photon yield are measured. The internal radiation efficiency is deduced. Its monotonic increase as n increases is explained by the increase in the spontaneous radiative rate with a radiative free carrier band-to-band recombination coefficient B=(1.2±0.3)×10−11 cm3 s−1.

Electronic states and the Stark shift in narrow band InSb quantum spherical layer

Electron states and the Stark shift in narrow band quantum spherical InSb layers are considered in frameworks of Kane model with respect to non-parabolicity of the dispersion law. An exact analytical solution of the corresponding Klein–Gordon equation for the model of impenetrable walls is obtained, and in addition to that a transcendent equation for determination of electron energetic spectrum is derived as well. The influence of the electric field is considered in frames of the perturbation theory, it is also shown that the value of the Stark shift is proportional to the second power degree of the field. Dependences of the electron energy versus the internal field values, external radius, and electric field are presented. The obtained results are compared with results obtained for the case with standard dispersion.

A 'Kane's dynamics' model for the active rack isolation system. Part 3: addition of umbilicals to the non-linear model

Boeing's Active Rack Isolation System (ARIS) isolates space-science experiments on the International Space Station against station-induced disturbances, at the rack-level. Part 1 of this documentation presented a linearised model of ARIS, hand-developed via Kane's method. Part 2 reported the use of software packages to develop and verify a corresponding nonlinear model, without umbilicals. Part 3, below, reports on: umbilical addition to the nonlinear model; model verification against simple truth models. Verification checks against truth models indicate that the proposed nonlinear model, when properly calibrated against experimental data, offers a high-fidelity representation of ARIS for simulation and controller-design purposes.

DESIGN & OPTIMIZATION OF AN I-RTD HYBRID THz OSCILLATOR BASED UPON In1−xGaxAs/GaSbyAs1−y HETEROSTRUCTURE SYSTEMS

An In 1− x Ga x As / GaSb y As 1− y hetero-system with staggered band-lineups as solid-state platform for design of an interband resonant double-barrier tunneling diode (I-RTD) based optically-pulsed (OT) hybrid device for generating THz oscillations is theoretically investigated. It is demonstrated that this optical I-RTD hybrid is compatible with the robust state-of-art 1.55 micron laser technology Multi-band wave equations in the framework of six-band Kane's model are applied for understanding the carrier dynamics when strain-induced effects are present. Simulation results for practical circuit implementations clearly show the superiority of this new oscillator concept.

Interband transitions in a narrow-gap InSb cylindrical quantum dot

Interband transitions in a narrow-gap InSb cylindrical quantum dot (QD) have been theoretically studied in the regime of strong dimensional quantization with allowance for a nonparabolic dispersion of electrons and light holes. The corresponding absorption coefficients and threshold frequencies for a QD array are calculated within the framework of a two-band Kane model for electrons and light holes and a parabolic dispersion law for heavy holes. These threshold frequencies fall in the IR range. Quantitative calculations are performed using the recent data of Moiseev et al. [1] on the growth of InSb quantum dots by liquid phase epitaxy.

Hidden symmetry and excitonic transitions in the quantum well

In this article it is shown that, Sommerfeld's coefficients for excitonic transitions in quantum wells are determined only with the principle quantum number within the framework of two-dimensional Coulomb potential. This is a consequence of hidden symmetry of two-dimensional Coulomb problem, conditioned by the existence of two-dimensional analog of the Runge–Lentz vector. For the narrow gap semiconductor quantum well with the non-parabolic dispersion law of electron and hole in the two-band Kane model it is shown that two-dimensional excitonic states are described in the frames of an analog of Klein–Gordon equation with the two-dimensional Coulomb potential. The non-stability of the ground state of the two-dimensional Kane's exciton is shown.

Effect of Quantizing Magnetic Field on Cyclotron Energy andCyclotron Effective Mass in Size Quantized Films with Non-ParabolicEnergy Band

The Fermi energy, cyclotron energy and cyclotron effective mass ofdegenerate electron gas in a size-quantized semiconductor thin filmwith non-parabolic energy bands are studied. The influences ofquantizing magnetic field on these quantities in two-band approximationof the Kane model are investigated. It is shown that the Fermi energyoscillates in a magnetic field. The period and positions of theseoscillations are found as a function of film thickness andconcentration of electrons. Cyclotron energy and cyclotron effectivemass are investigated as a function of film thickness in detail. Theresults obtained here are compared with experimental data on GaAsquantum wells.

Spin-Orbit Interaction in Symmetric Wells with Two Subbands

We investigate the spin-orbit (SO) interaction in two-dimensional electron gases in quantum wells with two subbands. From the 8x8 Kane model, we derive a new intersubband-induced SO term which resembles the functional form of the Rashba SO but is nonzero even in symmetric structures. This follows from the distinct parity of the confined states (even or odd) which obliterates the need for asymmetric potentials. We self-consistently calculate the new SO coupling strength for realistic wells and find it comparable to the usual Rashba constant. Our new SO term gives rise to a nonzero ballistic spin-Hall conductivity, which changes sign as a function of the Fermi energy (epsilonF) and can induce an unusual Zitterbewegung with cycloidal trajectories without magnetic fields.

MAGNETOPHONON RESONANCE IN MnxCdyHg1-x-yTe

The aim of this work is to analyze the band-structure parameters of Mn x Cd y Hg 1- x - y Te (MMCT) alloys by means of Magnetophonon Resonance (MPR) and to compare that obtained for Zn x Cd y Hg 1- x - y Te (ZMCT). MPR was observed for two samples of Mn x Cd y Hg 1- x - y Te (MMCT) (I- x =0.095 and y =0.09, II-0.04 and y =0.19). The measurements of MPR were performed in pulsed magnetic fields at different temperatures ranging from 77 K to 200 K. The several wide maxima are clearly visible on the experimental curves corresponding to four series of peaks. These series are related to three kinds of phonons analogous to ZMCT. The system of MPR peaks in MMCT is shifted significantly to the higher magnetic fields in comparison with the ZMCT resonance curves of approximately the same content of Zn . The value of effective mass obtained by MPR experiment is of 66% greater than those calculated in the framework of three-band Kane model, in which the value of Eg, was extracted from the photoconductivity data.

Optical band gap width in GaAs in megagauss magnetic fields

The band gap width in GaAs in magnetic fields of up to 10 MG is calculated using a five-band kp model. The selection rules for interband electron transitions in strong magnetic fields are found, and the dependences of the interband transition probabilities on a magnetic field are calculated. The electronic spectra calculated in the five-band model are compared with those calculated in the Kane model and in the tight-coupling approximation. The calculations are shown to agree with experimental data if the contribution from the density-of-states tails and excitonic effects to light absorption is taken into account.

Design and Simulation of a Mid-Infrared Quantum Cascade Laser Based on Ge-Si Superlattices

This paper presents a novel valance intersubband laser based on Si-based Si-Ge superlattices grown on a relaxed Si0.5Ge0.5 buffer layer. Effective mass theory is used to calculate the inplane valence subband dispersion of Si-Ge superlattices within 6×6 Kane model. Analysis of the inplane energy dispersion shows that the light-hole effective mass is inverted at off zone center region. The laser structure can be designed with a simple quantum cascade scheme. Our calculation shows that with the electrical pump, it is possible to achieve population inversion between the two subbands at local k space where the light-hole effective mass is inverted. Optical gain of the order 100/cm can be achieved with a pumping current density 10 kA/cm2.

Stark Tuning of Donor Electron Spins in Silicon

We report Stark shift measurements for 121Sb donor electron spins in silicon using pulsed electron spin resonance. Interdigitated metal gates on a Sb-implanted 28Si epilayer are used to apply the electric fields. Two quadratic Stark effects are resolved: a decrease of the hyperfine coupling between electron and nuclear spins of the donor and a decrease in electron Zeeman g factor. The hyperfine term prevails at magnetic fields of 0.35 T, while the g factor term is expected to dominate at higher magnetic fields. We discuss the results in the context of the Kane model quantum computer.

Electronic transport properties ofPbTeandAgPbmSbTe2+msystems

Transport calculations using the Boltzmann equation within energy-dependent relaxation time approximations were performed for $\mathrm{PbTe}$ and ${\mathrm{AgPb}}_{m}{\mathrm{SbTe}}_{2+m}$ (LAST-m) systems. We have used both the nonparabolic Kane model for the energy dispersion and the energy dispersion given by ab initio electronic structure calculations. For $\mathrm{PbTe}$ we find that the temperature dependence of the density of states effective mass ${m}_{d}$ is very important in order to have good agreement with experiment for electrical conductivity $\ensuremath{\sigma}$ and thermopower $S$. Transport calculations in $n$-type $\mathrm{PbTe}$ using the energy dispersion given by the ab initio electronic structure results in overestimation of $\ensuremath{\sigma}$ and underestimation of $S$ because the temperature dependence of ${m}_{d}$ cannot be incorporated in the calculation of the chemical potential. Transport calculations in $n$-type LAST-m systems using the nonparabolic Kane model for the energy dispersion show a small enhancement of the power factor $(\ensuremath{\sigma}{S}^{2})$ in $0--500\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ temperature range relative to $\mathrm{PbTe}$. The observed large ZT values of the LAST-12 and LAST-18 systems are a combination of a small enhancement of the power factor and a strong reduction in the thermal conductivity due to the formation of $\mathrm{Ag}\text{\ensuremath{-}}\mathrm{Sb}$ microstructures.

TERAHERTZ RADIATION IN SUPERLATTICES IN MODERATE ELECTRIC FIELD

We have studied the terahertz (THz) radiation in superlattices (SLs) in moderate electric field region (between 12 kV/cm and 25 kV/cm) from both theoretical and experimental aspects in this work. The THz emission intensity has been calculated for three samples of GaAs/Al 0.3 Ga 0.7 As SLs by using Kane model. The theoretical results show that the radiation intensity increases until the electric field F achieves a certain value between 14 kV/cm and 16 kV/cm for various samples, and then starts to roll off. The agreement of the calculated results with the experimental data demonstrates that the rolling of THz radiation intensity is due to the competition of field induced localization of wave functions and the increasing of the photon energy in THz radiation with increased electric fields. Furthermore, it is also shown that THz radiation intensity can be affected by the scattering of the randomly distributed Al atoms in the barriers.

Potential errors in a scheme of universal quantum gates in Kane’s model

We reinvestigate a plausible proposal for universal quantum gates in Kane's model, in which the authors assumed that electron spin is always downward under a background magnetic field and the value of the controlling parameters is varied instantaneously. We demonstrate that a considerable error appears, for example, in the $X$ rotation. As a result, the controlled operations do not work. This failure is caused by improper choice of the computational bases; actually, the electron spin is not always downward over time during quantum operations.

Are Markets Confused or Systematically Misinformed?

This article synthesizes the Fama-French and the Kane models of return behavior under conditions of investor disagreement. In Fama and French, misinformation is noise, while Kane models purposeful misinformation. The synthesis identifies empirical tests based on the difference between the behaviors of market returns under the two possible conditions. Returns are examined in four countries - Germany, Mexico, Thailand and Turkey - to test for rejection of the Fama-French hypothesis. We reject in Mexico, Thailand and Turkey but not in Germany. This suggests passive investment may increase insider rents under conditions of poor investor protection.