QUANTUM OSCILLATORY PHENOMENA IN A P-N-JUNCTION OF QUANTUM-WELLS

We consider tunnelling across a p-n junction (a tunnelling diode) wher e the motion on both sides is constrained by quantum wells (QW) in the direction perpendicular to the interface to form 2D n-type and p-type electron gases. Coulomb interactions are neglected. The Hamiltonian n ear an intersection of the dispersion curves, E(k), of the n side and the p side resembles that of a relativistic Dirac electron. An electro n, prepared in one of the QWs, will oscillate periodically between the two QWs with a frequency proportional to the tunnelling amplitude. In the tunnelling process, the velocity parallel to the interface is rev ersed resulting in periodic velocity oscillations similar to the Zitte rbewegung where in the present case the opposite directions of the vel ocity are separated in space. We also find that the eigenstates have f inite ''persistent'' circular currents which create magnetic moments o f several Bohr magnetons, typically. The noise spectrum, and the linea r response of the system are also obtained.