Electrothermal instabilities induced by a metastable electronic state in PbTe(Ga)

The electrothermal instabilities in high-resistance single crystals of PbTe(Ga) irradiated by infrared light are described phenomenologically. Instabilities show up in the form of periodic oscillations in the current in the sample circuit and in its temperature in sufficiently high electric fields. For observation of these phenomena it is important that the energy spectrum of the semiconductor contain metastable electronic states lying about 20 meV below the bottom of the conduction band.