Submicrometer control of two-dimensional–two-dimensional magnetotunneling in double-well heterostructures

Interwell two-dimensional--two-dimensional (2D-2D) tunneling in a density-imbalanced double-well heterostructure is studied in an in-plane magnetic field using a gated-bridge technique which does not require independent contacts to the two 2D electron layers. Two sharp peaks in the tunneling conductance at B{≤}1.3 T and B=5--6 T are explained using a linear-response theory which incorporates finite scattering and is based on a field-induced momentum shift of the two quantum wells' Fermi circles. A second gate is used to locally enhance tunneling on a submicrometer length scale.