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

We present measurements of the relaxation of frustrated charge configuratio ns via tunneling in a double quantum dot in the quantum Hall regime. We stu died transport through two quantum dots in series at each of three Landau l evel filling factors: nu=2, 3, and 4. The double dot conductance was measur ed as a function of the induced charge on each dot and of the interdot tunn el conductance to demonstrate the evolution of the charging diagram with in creasing interdot electron tunneling. At all three filling factors, we find that the evolution from well separated to joined dots is complete at an in terdot tunnel conductance G(int)congruent to e(2)/h, in contrast with the z ero magnetic field case. We also observe that the residual interaction ener gy relative to the charging energy increases above the zero field value. (C ) 1999 American Institute of Physics. [S0021-8979(99)04619-8].