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Exact ground state solution of shallow hydrogenic impurity states of a spherical parabolic GaAs/InAs quantum dot
摘要： The ground state spin magnetic moment current, binding energy, wave function and diamagnetic susceptibility of a shallow hydrogenic impurity located at the center of a parabolic spherical quantum dot are calculated analytically as a function of the dot size, interaction strength and confinement frequency. For comparison purposes, the results are discussed in the presence and in the absence of an impurity. Also, the dependence of the spin magnetic moment current on the spherical coordinates are derived, it is found that the spin magnetic moment current exhibits a peak structure and this current has a pronounced maximum for both small dot sizes and in the absence of impurities. Our results show that the impurities ground state binding energy enhances as the dot dimension decreases and depends strongly on the interaction strength as the dot size increases and reduces to zero in the bulk limit for large dimension of the dot. Moreover, the harmonic interaction has a strong influence on the diamagnetic susceptibility when the dot size increases where it decreases sharply in the presence of impurities while in the absence of impurities it decreases smoothly. In addition, the intensity of the magnetic field created by the spin magnetic moment current at the center of the quantum dot has been calculated. It is concluded that there is a critical value for characteristic parameters and the dot size for each type of semiconductor QD to give a specific function that might be important for nanotechnology manufacturing techniques.
关键词： Spherical quantum dot,Diamagnetic susceptibility,Harmonic e-e interaction,Donor impurity,Spin magnetic moment current
更新于2025-09-19 17:13:59
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Temperature effect on the binding energy and the diamagnetic susceptibility of a magneto-donor in Cylindrical Quantum Dot (GaAs/GaAlAs)
摘要： In this work, the effect of the temperature on the binding energy and the diamagnetic susceptibility of a shallow magneto-donor confined to move in a cylindrical quantum dot made out of GaAs/GaAlAs is studied within the effective mass approximation. We describe the quantum confinement by an infinite deep potential. The results show that when the temperature or the magnetic field increases, (i) the binding energy increases and (ii) the absolute value of the diamagnetic susceptibility decreases. Its effects depend strongly on the size of the CQD.
关键词： GaAs/GaAlAs,temperature effect,binding energy,cylindrical quantum dot,diamagnetic susceptibility,magneto-donor
更新于2025-09-19 17:13:59
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Influence of electric field on direct and indirect exciton in a concentrically coupled quantum ring heterostructure embedded in SiO2 matrix
摘要： Excitonic states of Concentric Double Quantum Ring (CDQR) heterostructures embedded in SiO2 matrix under the influence of electric field has been calculated theoretically using variational technique. CDQR has been confined in a quantum well of suitable width which serve as the height of the quantum ring along which the electric field is applied. Central barrier width, outer ring width and carrier location has been tuned to understand the localization of both direct and indirect excitons. Effect of ring dimension and electric field on the energy states of Inner Ring Exciton (IRE) and Outer Ring Exciton (ORE) has been determined. Tilting of conduction and valence bands due to the application of electric field invokes a triangular confinement to the carriers and the same has been discussed. Diamagnetic susceptibility which is merely an indicator of electron hole separation and intersubband transition energy has also been calculated for both symmetric and asymmetric quantum ring. Height of the QR has also been changed to study its effect on the diamagnetic susceptibility of an exciton.
关键词： Diamagnetic Susceptibility,Quantum Ring,Exciton,Binding energy,Electric Field
更新于2025-09-12 10:27:22