Coherent and sequential photoassisted tunneling through a semiconductor double-barrier structure.

We have studied the problem of coherent and sequential tunneling through a double-barrier structure, assisted by light considered to be present all over the structure, i.e., emitter, well, and collector as in the experimental evidence. By means of a canonical transformation and in the framework of the time-dependent perturbation theory, we have calculated the transmission coefficient and the electronic resonant current. Our calculations have been compared with experimental results and turn out to be in good agreement. Also, the effect on the coherent tunneling of a magnetic field parallel to the current in the presence of light has been considered.