WAVE PROPAGATION IN NEGATIVE DIFFERENTIAL CONDUCTIVITY MEDIA - N-GE

In study of transverse electromagnetic wave propagation in negative differential resistance medium provided by suitably oriented n-type germanium at 77 K, wave frequency is chosen to fall below critical scattering rates in this system (1 GHz), and sample dimensions are maintained below critical length for domain formation; wave amplification is noted and real and imaginary parts of conductivity are evaluated throughout d-c bias field range of range of resistivities.