We have investigated experimentally the magnetoresistance of strongly
asymmetric double-wells. The structures were prepared by inserting a thin
Al0.3Ga0.7As barrier into the GaAs buffer layer of a standard
modulation-doped GaAs/Al0.3Ga0.7As heterostructure. The resulting
double-well system consists of a nearly rectangular well and of a triangular
well coupled by tunneling through the thin barrier. With a proper choice of the
barrier parameters one can control the occupancy of the two wells and of the
two lowest (bonding and antibonding) subbands. The electron properties can be
further influenced by applying front- or back-gate voltage.Comment: 4 pages, 5 figures, elsart/PHYEAUTH macros; to be presented on the
EP2DS-15 Conference in Nara, Japan. Revised version. To appear in Physica