ИСТИНА

To determine the energy, temperature and pressure coefficients of iron deep level in PbTe we investigate temperature dependences of the resistivity and the Hall coefficient (T=4.2-300 K, B<0.07 T) in Pb1-yFeyTe under hydrostatic compression up to 10 kbar. It is shown that in PbTe doped with Fe, where the iron resonant level at T=4.2 K is very close to the top of the valence band [1], the effect of the increase of RH with increasing temperature is more pronounced: the Hall coefficient increases by more than an order of magnitude. Theoretical temperature dependences of the Hall coefficient, which are in satisfactory agreement with experimental ones, are calculated in the framework of the two-band Kane dispersion law assuming pinning of the Fermi level by the Fe resonant level, variation of the band gap with increasing temperature and pressure and degenerate statistics of charge carriers at low temperatures. It is revealed that at atmospheric pressure resonant Fe level situates approximately 18 meV below the valence band top. As the temperature rises, Fe level moves up towards the middle of the gap with the rate α=0.25 meV/K, while under pressure it moves almost parallel to the middle of the gap slightly shifting down at the rate g=–0.02 meV/kbar. Diagrams of the electronic structure rearrangement in Pb1-yFeyTe alloys with increasing temperature and under pressure are proposed