Electric transport and low-frequency noise characterization of $Bi_{2}Se_{3}$ topological insulator thin films.

New states of quantum matter, not directly related to conventional insulators and semiconductors, are represented by topological insulators. Due to a strong contribution of the surface to transport, these compounds have attracted an increasing interest. In order to better investigate the effect of intrinsic fluctuations on the surface conduction, a detailed characterization of the low-frequency noise has been made on $Bi_{2}Se_{3}$ thin films. The experiments have been performed by varying the samples thickness and geometry, in a temperature range from 300 down to 8 K, and as a function of dc bias current and gate voltage. The obtained results have shown standard thermal and shot noise contributions, while an unusual reduction of the $1/f$ noise component has been found. This behavior, especially evident in the low-temperature region, has been correlated with structural and dc electric transport properties. From the observations reported, a clear indication on the occurrence of the topological regime has been observed. Therefore, flicker noise measurement is a valid alternative technique to standard topological surface state spectroscopy.