The effect of cycle deformation on the AC conductivity of (Bi$_{0.3}$Sb$_{0.7}$)$_{2}$)Te$_{3}$ films

It has been found that the resistance of the Bi$_{0.3}$Sb$_{0.7}$)$_{2}$)Te$_{3}$ porous polycrystalline film fabricated by thermal vacuum evaporation at substrate temperature $T_s\le$ 363 K drastically decreases near the threshold AC frequency $\omega_0\approx$ 10$^5$ Hz as low as the resistance of dense films with $T_s\approx$ 423 K. After the action of $N\approx$ 10$^5$ cycles of mechanical deformation with amplitude $\varepsilon=\pm$ 1 $\times$ 10$^{-3}$ a.u., the film resistance increases by 1.5 times and the threshold frequency decreases in almost 10$^2$ times, which can qualitatively be accounted for by the model of microcontacting blocks.