  Te NMR studies were carried out for the bismuth telluride topological
insulator in a wide range from room temperature down to 12.5 K. The
measurements were made on a Bruker Avance 400 pulse spectrometer. The NMR
spectra were collected for the mortar and pestle powder sample and for single
crystalline stacks with orientations c parallel and perpendicular to field. The
activation energy responsible for thermal activation. The spectra for the stack
with c parallel to field showed some particular behavior below 91 K.
