Evidence of bistable shallow‐deep silicon donors in GaAs‐AlAs superlattices

We have investigated the electrical properties of silicon‐doped superlattices under hydrostatic pressure. Hall data are interpreted with a conduction model involving a nonmetastable shallow donor besides the metastable DX states lying in GaAs and AlAs layers. A change from a Γ miniband conduction into a X miniband conduction is induced by increasing pressure, showing that the shallow donor is linked with the X minimum of the superlattice miniband.