Measuring interactions between tunnel-coupled quantum dots in the quantum Hall regime

Abstract

We present measurements of the relaxation of frustrated charge configurations via tunneling in a double quantum dot in the quantum Hall regime. We studied transport through two quantum dots in series at each of three Landau level filling factors: ν=2, 3, and 4. The double dot conductance was measured as a function of the induced charge on each dot and of the interdot tunnel conductance to demonstrate the evolution of the charging diagram with increasing interdot electron tunneling. At all three filling factors, we find that the evolution from well separated to joined dots is complete at an interdot tunnel conductance Gint≅e2/h, in contrast with the zero magnetic field case. We also observe that the residual interaction energy relative to the charging energy increases above the zero field value.