Quantum interference effect in GaAsAlGaAs double quantum wells

Quantum interference properties of GaAsAlGaAs symmetric double quantum wells were investigated in a magnetic field parallel to heterointerfaces at 1.9 K. For two types of samples used in our experiments, two GaAs quantum wells with the same width of 60 Å are separated by an AlGaAs barrier layer of 120 Å and 20 Å thick, respectively. The channels with the length of 2 μm are defined by alloyed ohmic contacts. The conductance oscillation as a function of the magnetic flux Φ(= Bs) was observed and oscillation period is approximately equal to he. The results are in agreement with the theoretical expectation of the Aharonov-Bohm effect. Conductance oscillations are apparent slightly in the samples with a thinner AlGaAs barrier.