scholarly journals Mobility Enhancement in Square Quantum Wells: Symmetric Modulation of the Envelop Wave Function

2010 ◽  
Vol 20 (3) ◽  
pp. 193
Author(s):  
Doan Nhat Quang ◽  
Nguyen Huyen Tung ◽  
Nguyen Trung Hong ◽  
Tran Thi Hai
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Low Temperature ◽  
Quantum Wells ◽  
Quantum Transport ◽  
Variational Approach ◽  
Theoretical Study ◽  
Recent Experimental Data ◽  
Carrier Distribution ◽  
Analytic Expressions

We present a theoretical study of the effects from symmetric modulation of the envelop wave function on quantum transport in square quantum wells (QWs). Within the variational approach we obtain analytic expressions for the carrier distribution and their scattering in symmetric two-side doped square QWs. Roughness-induced scattering are found significantly weaker than those in the asymmetric one-side doped counterpart. Thus, we propose symmetric modulation of the wave function as an efficient method for enhancement of the roughness-limited QW mobility. Our theory is able to well reproduce the recent experimental data about low-temperature transport of electrons and holes in two-side doped square QWs, e.g., the mobility dependence on the channel width, which have not been explained so far.

scholarly journals The Mobilities of Carriers Confined in a Single-side Doped Square Quantum Wells Dependence on Temperature

2017 ◽  
Vol 33 (2) ◽  
Author(s):  
Tran Thi Hai
Keyword(s):  
Quantum Wells ◽  
Variational Approach ◽  
Acoustic Phonon ◽  
Electron Gas ◽  
Recent Experimental Data ◽  
Dimensional Electron ◽  
Carrier Distribution ◽  
Single Side ◽  
Analytic Expressions ◽  
Dimensional Electron Gas

A theory is given of the mobility of a two-dimensional electron gas at high temperature in single-side square quantum wells. Within the variational approach, we obtain analytic expressions for the carrier distribution, and autocorrelation functions for various scattering mechanisms. We examine the dependence of the mobilities of carriers on the temperature. Our theory is able to well reproduce the recent experimental data on transport in 1S-doped square QWs, e.g., acoustic-phonon partial mobility dependence on temperature for single-side modulation doped square quantum wells.

scholarly journals Effect of Spontaneous Polarization Charges on the Electron Mobility in ZnO Surface Quantum Wells

2015 ◽  
Vol 19 (4) ◽  
Author(s):  
Nguyen Thanh Tien ◽  
Le Tuan ◽  
Doan Nhat Quang
Keyword(s):  
Surface Roughness ◽  
Low Temperature ◽  
Quantum Wells ◽  
Spontaneous Polarization ◽  
Theoretical Study ◽  
Impurity Scattering ◽  
Hydrogen Ions ◽  
Dimensional Electron ◽  
Surface Roughness Scattering ◽  
Dimensional Electron Gas

We present a theoretical study of the effect due to spontaneous polarization of ZnO on the low-temperature mobility of the two-dimensional electron gas (2DEG) in a ZnO surface quantum well (SFQW). We proved that for the O-polar face this causes an attraction of electrons by the positive charges bound on the surface, while for the Zn-polar face a repulsion of them far away therefrom by the negative bound charges of the same magnitude. Accordingly, surface roughness scattering is drastically enhanced in the former case, but reduced in the latter one. Therefore, the low-% temperature 2DEG mobility in ZnO SFQWs with O-polar face is found to be dominated by surface roughness. Our theory was illustrated for the sample prepared by bombardment of the O-polar face by 100-eV hydrogen ions. The surface roughness scattering enables an explanation of the 2DEG mobility, especially, the reason of low values for the mobility in the dependence from the carrier density which has not been understood when starting from impurity scattering.

scholarly journals Effect from Doping of Quantum Wells on Enhancement of The Mobility Limited by One-Interface Roughness Scattering

2011 ◽  
Vol 21 (3) ◽  
pp. 211
Author(s):  
Tran Thi Hai ◽  
Nguyen Huyen Tung ◽  
Nguyen Trung Hong
Keyword(s):  
Quantum Wells ◽  
Correlation Length ◽  
Variational Approach ◽  
Carrier Density ◽  
Enhancement Factor ◽  
Theoretical Study ◽  
Interface Roughness ◽  
Interface Roughness Scattering

We present a theoretical study of the effect from doping of quantum wells (QWs) on enhancement of the mobility limited by one-interface roughness scattering. Within the variational approach, we introduce the enhancement factor defined by the ratio of the overall mobility in symmetric two-side doped square QWs to that in the asymmetric one-side counterpart under the same doping and interface profiles. The enhancement is fixed by the sample parameters such as well width, sheet carrier density, and correlation length. So, we propose two-side doping as an efficient way to upgrade the quality of QWs. The two-interface roughness scattering is also incorporated to make comparison.

scholarly journals Low-Temperature Properties of Compensated Ge Films Used for Cryogenic Thermometers

2002 ◽  
Vol 719 ◽  
Author(s):  
V. F. Mitin ◽  
V. V. Kholevchuk ◽  
V. K. Dugaev ◽  
M. Vieira
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Low Temperature ◽  
Theoretical Study ◽  
Temperature Sensors ◽  
Temperature Resistance ◽  
Gaas Substrates ◽  
Heavily Doped ◽  
Low Temperature Resistance ◽  
Good Agreement

AbstractLow temperature microsensors are designed for cryogenic applications. As a material for the sensors we use heavily doped compensated Ge films deposited on the semi-insulating GaAs substrates. We present the results of experimental and theoretical study of the low temperature resistance as a function of temperature and magnetic field for some models of temperature sensors. The computer simulations show a good agreement with experimental data.

CARRIER CAPTURE IN SEMICONDUCTOR QUANTUM WELL LASERS: A QUANTUM TRANSPORT ANALYSIS

1998 ◽  
Vol 09 (04) ◽  
pp. 1211-1233 ◽  
Author(s):  
LEONARD F. REGISTER
Keyword(s):  
Wave Function ◽  
Quantum Wells ◽  
Quantum Transport ◽  
Golden Rule ◽  
Carrier Wave ◽  
Carrier Capture ◽  
The Past ◽  
Semiconductor Quantum Wells ◽  
Semiconductor Quantum Well ◽  
Transport Analysis

A quantum transport-based analysis of the essential physics of carrier capture in semiconductor quantum wells is presented. First, the past progression of models of carrier capture by quantum wells is briefly reviewed. Then carrier capture is modeled using the Schrödinger Equation Monte Carlo (SEMC) quantum transport simulator. In addition to reproducing familiar effects, these simulations exhibit significant effects associated with partial phase-coherence of the carrier wave-function across the well which cannot be modeled via classical or perturbative Golden Rule calculations, and address fundamental transport limitations often overlooked in Golden Rule calculations. However, this analysis also points to simple changes that could significantly improve, although not perfect, the treatment of carrier capture via these latter more conventional approaches.

scholarly journals In-Medium Strangeness Production and Hyperon-Potentials

2019 ◽  
Vol 26 ◽  
pp. 83
Author(s):  
T. Gaitanos ◽  
A. Violaris ◽  
L. Fabbietti ◽  
M. Steffen ◽  
J. Wirth
Keyword(s):  
Experimental Data ◽  
Neutron Star ◽  
Theoretical Study ◽  
Nuclear Astrophysics ◽  
The Other ◽  
Recent Experimental Data ◽  
Theoretical Treatment ◽  
Kaon Production ◽  
Microscopic Models ◽  
Open Issue

A hot topic of current research concerns the Equation of State (EoS) of nucleons and, in particular, of hyperons in dense nucleonic media. The study of the EoS at nucleon densities far beyond saturation has been initiated several decades ago, however, the behavior of the EoS for strangeness particles is still an open issue. The strangeness part of the EoS is very important not only for the physics of exotic (hyper)nuclei, but also crucial for nuclear astrophysics, e.g., neutron star physics.Here we present our recent investigations related to the theoretical treatment of in-medium hyperon-interactions as well as first preliminary experimental results from pion-induced reactions. The theoretical study is based on the well-established Non-Linear Derivative (NLD) model, which is extended to the strangeness sector via SU(6) symmetry arguments. It turns out that the NLD-predictions are consistent with microscopic models based on the chiral-EFT theory. On the other hand, recent experimental HADES-data on hyperon and kaon production from pion-induced reactions indicate sensitivities on the underlying in-medium hyperon potentials. We thus conclude that, the recent experimental data from pion-induced reactions will definitely set stringent constraints on the still less understood hyperon-potentials in nucleonic matter.

TWO-LEVEL TUNNELLING MODEL DESCRIPTION OF THERMAL CONDUCTIVITY FOR CuxSn1-x METALLIC GLASSES AT LOW TEMPERATURE

2003 ◽  
Vol 17 (11) ◽  
pp. 2259-2271
Author(s):  
G. M. BHUIYAN ◽  
MD. SHAHJAHAN ◽  
ISSAM ALI ◽  
S. M. MUJIBUR RAHMAN
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Low Temperature ◽  
Metallic Glasses ◽  
Model Description ◽  
Recent Experimental Data ◽  
Model Parameters ◽  
Scattering Mechanism ◽  
Fitting Procedure ◽  
Theoretical Results

The two level tunnelling model is applied to analyze recent experimental data on low temperature thermal conductivity of Cu x Sn 1-x metallic glasses. An extra scattering mechanism due to Rayleigh is introduced to describe three characteristic regions of conductivity. Model parameters are determined using least-squares fitting procedure. Results derived from the parameters allow one to predict several interesting low temperature properties of metallic glasses in particular the characteristic plateau of conductivity. Theoretical results are also compared and contrasted with those of other metallic and non-metallic systems, and both common and uncommon features that exist between them are discussed.

DIFFUSION OF LIGHT ADATOMS ON SOLID SURFACES

1995 ◽  
Vol 09 (06) ◽  
pp. 307-318
Author(s):  
L. Y. CHEN ◽  
S. C. YING
Keyword(s):  
Experimental Data ◽  
Low Temperature ◽  
Theoretical Approach ◽  
Temperature Regime ◽  
Quantum Tunneling ◽  
Entire Range ◽  
Solid Surfaces ◽  
Recent Experimental Data ◽  
Thermally Activated ◽  
Theoretical Results

We present a brief review of a theoretical approach to the diffusion of light adatoms that covers the entire range from the classical regime of thermally activated hopping to the low temperature regime of quantum tunneling between adjacent sites. We compare our theoretical results with recent experimental data for the system H/Ni(100). We also contrast our results with those obtained from the quantum transition state approach.

scholarly journals ELECTROROTATION OF COLLOIDAL SUSPENSIONS

2003 ◽  
Vol 17 (01n02) ◽  
pp. 221-225 ◽  
Author(s):  
J. P. HUANG ◽  
K. W. YU ◽  
G. Q. GU
Keyword(s):  
Experimental Data ◽  
Cell Shape ◽  
Theoretical Study ◽  
Colloidal Suspensions ◽  
Shape Effect ◽  
Oblate Spheroidal ◽  
Theoretical Predictions ◽  
Analytic Expressions ◽  
Particle Shape Effect ◽  
Good Agreement

We investigate the pressure effect on the eletrorotation (ER) spectrum of living cell suspensions by considering the particle shape effect. Based upon the spectral representation theory, we consider coated oblate spheroidal particles and present a theoretical study of ER spectrum. Analytic expressions for the characteristic frequency as well as the dispersion strength can be obtained, thus simplifying the fitting of experimental data. From the theoretical analysis, we find that the cell shape, coating as well as material parameters can change the ER spectrum. We demonstrate good agreement between our theoretical predictions and experimental data on human erythrocytes suspensions.

The X(3) model for the modified Davidson potential in a variational approach

2017 ◽  
Vol 26 (09) ◽  
pp. 1750054 ◽  
Author(s):  
M. Alimohammadi ◽  
H. Hassanabadi
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Wave Equation ◽  
Variational Method ◽  
Collective Behavior ◽  
Variational Approach ◽  
Energy Spectra ◽  
Transition Rates ◽  
Similar Work ◽  
Davidson Potential

In this work, we investigate the [Formula: see text]-rigid version of Bohr–Hamiltonian for the modified Davidson potential. Since the corresponding wave equation cannot be solved analytically, we apply the variational method. The related wave function, energy spectra and transition rates are determined. In order to evaluate our results, we fit the formula for the energy spectra to the available experimental data for some nuclei and compare the obtained standard error with the corresponding one in other similar work. Moreover, we study the collective behavior of these nuclei through the evolution of two quantities [Formula: see text] and [Formula: see text] in terms of number of valence nucleons.

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