Self-assembled InAs quantum dots to investigate the tunneling between edge states in an AlGaAs/GaAs double quantum well system

Self-assembled InAs quantum dots (QDs) embedded close to the tunnel barrier in the upper well of the double quantum well system act as a sensitive probe to investigate the tunneling between the edge states. In the monolayer configuration, when the tunnel interaction between the edge states was absent, the Hall resistance exhibited well-developed and quantized Hall plateaus at integer filling factors. However, in bilayer configuration, no Hall plateaus were seen and an abrupt increase in the resistance was observed at B=2.1 T, whereas no such anomalies were found in the control sample. This behavior appears to have its origin from the interaction between the edge state electrons and QDs as they tunnel across the barrier due to the difference in chemical potential between the upper and lower well.