The Effect of Band Filling on the Width of the Minigaps on Long-Period One-Dimensional Superlattices.
Technical rept. Sep 73-Oct 74,
COLORADO UNIV BOULDER DEPT OF ELECTRICAL ENGINEERING
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In superlattices with a long period greater than or approximately equal to 100A the miniband structure depends noticeably on the number of free electrons present and on how those electrons are distributed in energy. The minigap width between the first and second miniband decreases at first rapidly, then slowly, with an increasing number of electrons in the lowest miniband. For an exactly full first miniband the free-electron dielectric constant for perturbations of the superlattice wavelength is large the Kohn anomaly and highly non-linear. Transferring electrons into the second miniband increases the minigap width. For strongly inverted non-equilibrium distributions an electrostatic instability can occur in the band structure under certain extreme conditions.
- Solid State Physics