The electronic structure of the impurity d-levels of interstitial Mni in a GaAs quantum well was found to create deeply bound donor states located within the band gap. This behavior resulted from lowering the symmetry of the band states in 2DEG, which, in turn, lifted symmetry bans on the hybridization matrix elements. An impurity-assisted tunnelling current was enabled by discrete bound donor states with energies located below the first conduction quantum well sub-band.

Resonance Tunneling through a Single Interstitial Mn Impurity in a GaAs Quantum Well. P.Dahan: Physica E, 2008, 40[5], 1665-7