Controllable electron g-factors in HgMnTe quantum spheres

National Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences P.O. Box 912, Beijing 100083, PRC

Corresponding author: zhuyh@semi.ac.cn

Received: 30 November 2007
Accepted: 18 March 2008

Abstract

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 R_c; however, by modulating the nanocrystal size their absolute values can be turned to be even 400 times larger than those in undoped cases.