Far-infrared photoconductivity as a probe for non-equilibrium phase transitions in n-GaAs

A strong enhancement of the cyclotron resonance induced FIR-photoconductivity has been observed in n-GaAs close to the threshold of impact ionization breakdown. The results are discussed in terms of phase transitions far from equilibrium showing that the photoconductivity reflects the Curie-Weiss behaviour of the generalized susceptibility.