Xh. Wang et al., COUPLING BETWEEN THE TRANSVERSE AND LONGITUDINAL COMPONENTS OF AN ELECTRON IN RESONANT-TUNNELING, Physical review. B, Condensed matter, 55(15), 1997, pp. 9340-9343
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.