Dynamic Tunneling

In the epoch of information technologies, tunneling phenomena have become an important area of solid-state physics. The specifics of electron dynamics in crystals along with the extreme sensitivity of the possibility of tunneling to the parameters of both the particle itself and the barrier significantly differentiate interband tunneling from the standard picture of passage through a potential barrier. Soon after the creation of lasers, it became clear that the tunneling effect was also the determinative mechanism of interaction between powerful electromagnetic radiation and atoms, molecules, and solid bodies. The unifying effect for these two seemingly different groups of phenomena is their critical dependence on the temporal dynamics of the tunneling process. This report tells the history of the development of these concepts and their use to describe the dependence of the parameters of the interband tunnel effect on the structure of the electron spectrum of a crystal, the critical role of interaction between electrons and phonons, and the influence of the tunnel effect on the optical absorption spectra of crystals. It is also shown how the processes of multiphoton absorption gradually transform into the tunnel effect as the intensity or frequency of an alternating external field changes.