Carrier scattering processes in Bi1.08Sn0.02Sb0.9Te2S(BSSTS) topological insulator (TI) were studied using two independent methods: four-probe resistance measurements together with nonresonant microwave absorption (NMA). We obtained temperature dependences of resistance and NMA amplitude of BSSTS thin flakes. At low temperatures (T<100 K) BSSTS resistance behavior is determined by contribution of metallic topological surface states. The comparison of the results obtained by both methods allows us to make a conclusion that scattering time is larger than measurement frequency. It implies that scattering events are rare and gives indirect evidence of weak antilocalization effect. To study this phenomenon, we obtained magnetic field dependences of resistance and NMA of BSSTS. Results exhibit clear evidence of weak antilocalization contribution to TI conductivity. Analysis of the results allowed us to estimate phase coherence length lϕ at 1.5 K and 4.2 K temperatures. Obtained values of lϕ are close to 400 nm and relatively high in comparison with similar bismuth chalcogenide compounds. That makes BSSTS attractive for future applications at spintronics.
$^1$Kazan Federal University, 420008 Kazan, Russia\
$^2$Zavoisky Institute for Physics and Technology, Kazan Scientific Center RAS
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