Effect of the spin-orbit interaction on intersubband electron transition in GaAs/AlGaAs quantum well heterostructures

We have calculated matrix elements for the electron intersubband transitions in rectangular, triangular and double quantum wells using 8×8 Kane model that takes into account the spin-orbit interaction, the contribution of which is due to the lack of a center of inversion in the GaAs/AlGaAs heterostructures. It is shown that this contribution determines the value of the intersubband transition probability in a rectangular quantum well for normal incidence absorption. We also show that large errors occur if the transition matrix elements are calculated in a single-band model that takes into account only the dependence of electron effective mass on the semiconductor compound without including the electron spectrum nonparabolicity.