Improved projected Green's function approach to electron tunneling lifetime calculations in quantum wells

We demonstrate that the use of an optimal initial state of a wave function generated using Lanczos method allows the previously proposed projected Green's function approach to predict the tunneling lifetime of a particle crossing a double quantum well with a considerably improved accuracy. It is further revealed that the electron tunneling lifetime of such system depends linearly or quadratically on the barrier thickness or the well width. We also investigate the asymmetric double quantum well structure and find that the electron tunneling lifetime in it is strongly dependent on barrier thickness. Finally, we discuss the possible experimental designs to observe the above-mentioned tunneling features.