ANALYTICAL FORMALISM FOR DETERMINING QUANTUM-WIRE AND QUANTUM-DOT BAND-STRUCTURE IN THE MULTIBAND ENVELOPE-FUNCTION APPROXIMATION

被引:319
作者
SERCEL, PC
VAHALA, KJ
机构
[1] Department of Applied Physics, California Institute of Technology, Thomas J. Watson Sr. Laboratories of Applied Physics (Mail Stop 128-95), Pasadena
来源
PHYSICAL REVIEW B | 1990年 / 42卷 / 06期
关键词
D O I
10.1103/PhysRevB.42.3690
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We describe a new formalism for determining energy eigenstates of spherical quantum dots and cylindrical quantum wires in the multiple-band envelope-function approximation. The technique is based upon a reformulation of the KP theory in a basis of eigenstates of total angular momentum. Stationary states are formed by mixing bulk energy eigenvectors and imposing matching conditions across the heterostructure interface, yielding dispersion relations for eigenenergies in quantum wires and quantum dots. The bound states are studied for the conduction band and the coupled light and heavy holes as a function of radius for the GaAs/AlxGa1-xAs quantum dot. Conduction-bandvalence- band coupling is shown to be critical in a type-II InAs/GaSb quantum dot, which is studied here for the first time. Quantum-wire valence-subband dispersion and effective masses are determined for GaAs/AlxGa1-xAs wires of several radii. The masses are found to be independent of wire radius in an infinite-well model, but strongly dependent on wire radius for a finite well, in which the effective mass of the highest-energy valence subband is as low as 0.16m0. Implications of the band-coupling effects on optical matrix elements in quantum wires and dots are discussed. © 1990 The American Physical Society.
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页码:3690 / 3710
页数:21
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