Influence of the Fermi-liquid interaction of free-carriers on the form of absorption edge in semiconductors

Conditions for existence of the Fermi-liquid interaction of free-carriers may be realized in highly doped semiconductors. This interaction causes the change of the density of states of electron gas close to the Fermi surface. It is possible to detect this change of the density of states using the absorption spectra of the degenerated semiconductors. It is shown that the absorption spectra of the compounds Pb_0.81Sn_0.19Te at the temperatures close to the helium temperature may be described with allowance for the Fermi-liquid interaction of free-carriers.