Admittance and Permittivity in Doped Layered $TlGaSe_2$ Single Crystals

In doped $TlGaSe_2$ crystals the phase transitions at low temperatures (100-170 K) were observed using admittance and dielectric spectroscopy in a temperature range of 80-320 K. The admittance and permittivity measurements in the studied samples indicated that after Fe or Tb doping by impurities with concentrations $N_\text{imp}$ < 0.5 at.% nonequilibrium electronic phase transition is observed. Doping with $N_\text{imp}$ > 0.5 at.% resulted in full suppression of this phase transition presence.