Electrons in GaAs/Ga_(1-x)Al_xAs superlattices: Spin and orbital states in a magnetic field

摘要

Spin and orbital properties of electrons in GaAs/Ga_(1-x)Al_xAs superlattices (SLs) in an external longitudinal and transverse magnetic field are considered. A five-level P ? p model of the band structure is used, accounting for nonparabolicity and nonsphericity of the conduction band in III-V compounds as well as their inversion asymmetry. The electron-spin g values are computed as functions of superlattice spacings. It is shown that, in the transverse-field configuration, the g value is different for various electron locations in an SL. Transverse and longitudinal cyclotron masses are calculated and compared with available experimental data for various GaAs/Ga_(1-x)Al_xAs SLs. Finally, orbital electron states in short SLs in a transverse magnetic field are described for different field intensities. In addition to the standard Landau levels unexpected states are found whose energies have a strong quadraticlike field dependence. The origin of the states is investigated.