THE SINGLE-LAYER BILAYER TRANSITION OF ELECTRON SYSTEMS IN ALGAAS/GAAS/ALGAAS QUANTUM WELLS SUBJECT TO IN-PLANE MAGNETIC FIELDS

摘要

Equilibrium properties of electrons in double-heterojunction AlGaAs/GaAs/AlGaAs structures are investigated theoretically, using a fully self-consistent numerical method. The transition from single to bilayer electron systems is discussed for structures with varying distance between interfaces as a function of the in-plane magnetic field strength. A phenomenon of separability of the energy dispersion curves in parts corresponding to electrons in either the first or the second layer is analysed in detail. The magnetic-field-induced variation in the effective distance between electron layers is compared to the constant layer separation in standard double-well structures. Because the barrier between interfaces is relatively small and soft, the van Hove singularities in the 2D density of states are expected to be more easily detectable than in double-well systems. The cyclotron mass, proportional to the density of states and characterizing the electron motion in tilted magnetic fields, is calculated as a function of in-plane magnetic field. The separability of the energy spectra resulting in tilted cyclotron orbits is demonstrated on the basis of a classical picture of an electron moving in crossed electric and magnetic fields. [References: 14]