Soft Plasma Mode in GaAs

Abstract

Pytte and Thomas have predicted that in samples showing the Gunn effect the plasma frequency ${\omega }_p$ will go to zero as the electric field approaches the Gunn threshold. Here we calculate ${\omega }_p$ for GaAs, using a two-valley model, and find that (1) the actual variation with field is somewhat different from that predicted and (2) ${\omega }_p$ will not vanish in samples with carrier concentration greater than about ${10}^{18}$ / ${\mathrm{cm}}^3$.