COUPLING BETWEEN THE TRANSVERSE AND LONGITUDINAL COMPONENTS OF AN ELECTRON IN RESONANT-TUNNELING

In this paper we present formulas for the transmission coefficient in multibarrier heterostructures when taking into account the space-depen dent electron effective mass and the coupling between components of th e motion of an electron in directions parallel and perpendicular to th e interfaces. We find that the coupling leads to a decrease of the eff ective barrier height seen by the electron. The numerical calculations are carried out for the double- and triple-barrier heterostructures c onsisting of GaAs/Ga1-xAlxAs. Our results show that the coupling effec t leads not only significantly to a shift of resonant peaks toward the low-energy region, but also causes the broadening of resonant peaks a nd the reduction of the peak-to-valley ratio in the transmission spect rum. The coupling becomes more pronounced for higher-lying resonant st ates. In addition, the variation of the coupling strength with the con centration x of Al is also investigated.