BEHAVIOR OF CARRIERS IN DELTA-DOPED QUANTUM-WELLS UNDER INPLANE MAGNETIC-FIELDS

Self-consistent electronic structure calculations of delta-doped quant um wells (QW) in the presence of in-plane magnetic fields B up to 20 T esla are carried out within the frameworks of the effective mass and t he local density approximations. QWs composed of two layers of Ga1-xAl xAs, separated by a layer of GaAs with a donor delta-doped sheet in th e center, are considered. The width of the GaAs layer was varied from 100 to 400 Angstrom. It is shown that the diamagnetic shift increases with the increasing of the GaAs QW width. The magnetic held induces re markable changes in the energy dispersions of electrons and holes, alo ng an in-plane direction perpendicular to B. The most striking effect occurs in the nature of the band gap of these systems. We found that t he valence band displays a double-maximum character instead of a singl e maximum at the center of the Brillouin zone. (C) 1996 John Wiley & S ons, Inc.