Controllable electron g-factors in HgMnTe quantum spheresY.-H. Zhu and J.-B. Xia
National Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences P.O. Box 912, Beijing 100083, PRC
received 30 November 2007; accepted in final form 18 March 2008; published May 2008
published online 21 April 2008
The electronic structure and Landé electron g-factors of manganese-doped HgTe quantum spheres are investigated, in the framework of the eight-band effective-mass model and the mean-field approximation. It is found that the electronic structure evolves continuously from the zero-gap configuration to an open-gap configuration with decreasing radius. The size dependence of electron g-factors is calculated with different Mn-doped effective concentration, magnetic field, and temperature values, respectively. It is found that the variations of electron g-factors are quite different for small and large quantum spheres, due to the strong exchange-induced interaction and spin-orbit coupling in the narrow-gap DMS nanocrystals. The electron g-factors are zero at a critical point of spherical radius Rc; however, by modulating the nanocrystal size their absolute values can be turned to be even 400 times larger than those in undoped cases.
73.21.La - Quantum dots.
75.50.Tt - Fine-particle systems; nanocrystalline materials.
76.30.Fc - Iron group (3d) ions and impurities (Ti-Cu).
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