Quantum interference of electrons transmitted throughout a double-barrier resonant tunnelling structure under a perpendicular magnetic field

Abstract

Recently, we have discovered a fine oscillatory structure (FOS) of the current flowing through resonant tunnelling devices consisting basically of two very thin AlAs barriers separated by a GaAs quantum well. In this work we have found two striking properties of FOS in a magnetic field applied normally to the current flow: (i) a phase shift of the FOS on the bias-voltage scale which is proportional to the squared induction of the magnetic field; (ii) rapid oscillatory-type fall-off in FOS amplitude with increasing magnetic field. We demonstrate, using a simple quantitative model, that both properties can be consistently explained in terms of quantum interference between electrons which escaped from the quantum well and those partly reflected at a potential step on the collector side of the device. The physical conditions necessary for the appearance of FOS are discussed.