Intrinsic coupling mechanisms between two-dimensional electron systems in double quantum well structures

We report low-temperature magnetoresistivity measurements of a gated double-layer electron system comprising two parallel two-dimensional electron systems (2DES’s) separated by a tunnel barrier of sufficient width to permit only incoherent interlayer tunneling. We find that the trajectories of the diagonal resistivity maxima as a function of gate bias and magnetic field deviate from those expected for two uncoupled 2DES’s with electron densities constant in magnetic field. These deviations derive from two distinct coupling mechanisms. First, jumps in the Fermi energy of each 2DES engender an interlayer charge transfer which produces sharp kinks in the resistivity maxima trajectories. Second, the resistivity trajectories of one 2DES are affected by the development of an asymmetric electron potential profile produced as the other 2DES populates and undergoes a transition from insulating to metallic behavior. These two coupling mechanisms are intrinsic to the realization of double-layer electron systems in remotely doped layered semiconductor structures.