An Investigation of Magnetic Field Effects on Energy States for Nanoscale InAs/GaAs Quantum Rings and Dots

Yiming LI  Hsiao-Mei LU  

IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.3   pp.466-473
Publication Date: 2003/03/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on the 2002 IEEE International Conference on Simulation of Semiconductor Processes and Devices (SISPAD'02))
energy states,  magnetic field effects,  quantum rings and dots,  InAs/GaAs,  computer simulation,  

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In this paper, we investigate the electron-hole energy states and energy gap in three-dimensional (3D) InAs/GaAs quantum rings and dots with different shapes under external magnetic fields. Our realistic model formulation includes: (i) the effective mass Hamiltonian in non-parabolic approximation for electrons, (ii) the effective mass Hamiltonian in parabolic approximation for holes, (iii) the position- and energy-dependent quasi-particle effective mass approximation for electrons, (iv) the finite hard wall confinement potential, and (v) the Ben Daniel-Duke boundary conditions. To solve the 3D nonlinear problem without any fitting parameters, we have applied the nonlinear iterative method to obtain self-consistent solutions. Due to the penetration of applied magnetic fields into torus ring region, for ellipsoidal- and rectangular-shaped quantum rings we find nonperiodical oscillations of the energy gap between the lowest electron and hole states as a function of external magnetic fields. The nonperiodical oscillation is different from 1D periodical argument and strongly dependent on structure shape and size. The result is useful to study magneto-optical properties of the nanoscale quantum rings and dots.