MOTT TRANSITION IN COLD SEMICONDUCTORS

We discuss the Mott transition when a semiconductor is externally excited at low temperatures. We demonstrate that hysteresis is inevitable unless a phase separation occurs at higher temperatures or lower average excitation densities than necessary for the predicted ionization catastrophe. The critical temperature and pair density for hysteresis in Ge is of the order 6K and 3 · 1016 cm-3, respectively, for a model involving dynamical screening. © 1978.