Autori: J. P. Setrajcic, S. M. Stojkovic, D. Lj. Mirjanic, S. M. Vucenovic, Dusan Popov

Editorial: Materials Science Forum, 413, p.33 - 38, 2003.

Rezumat:

The dispersion law and spectral weights of electrons in perturbed thin film structures with two sublattices was derived by the method of two-time, single-electron Green’s functions. In variance from simple cubic structure, electron energy zone splits into two allowed energy bands and forbidden energy gap appears. In contrast to continual energy zone of allowed electron states in bulk crystals, the energy spectra in ultrathin films are discrete. The number of possible energy levels is equal to the double number of film layers along bounded direction. We also analyzed the in
uence of perturbation energy parameters on electron energy spectra. Increase of the electron energy at the
surfaces induces the shift of the spectrum towards higher energies. The width of forbidden energy gap has the greatest value, when electron surface energies are not perturbed. When the transfer energy of electrons at the surfaces increase the spectrum broadens, while width of forbidden gap decreases. The determination of electron space distribution has shown existence of localized states. Through boundary condition variations it is possible to induce appearance of energy gaps inside the spectra (the allowed energy bands of thin film become narrower than than those of the bulk) or appearance of localized
states (that lie outside bulk limits).

Cuvinte cheie: electrons, sublattice, thin films