[13a-D511-1~12] 9.4 Thermoelectric conversion

△ [13a-D511-8] Thermoelectric properties of a topological insulator Bi_2−xSb_xTe_3−ySe_y surface: Influence of ionic disorders

〇Takahiro Chiba¹, Takashi Komine², Saburo Takahashi³ (1.NIT-Fukushima Col., 2.Ibaraki Univ., 3.AIMR-Tohoku Univ.)

Keywords:topological insulator, thermoelectric effect, impurity scattering

We theoretically study thermoelectric properties on a surface of topological insulator, Bi_2−xSb_xTe_3−ySe_y (BSTS), with ionic disorder introduced by elemental substitution. Assuming two types of ionic impurity models, a Coulomb-type long-range potential and a delta-function-type short-range potential, we calculate thermoelectric power and ZT based on Boltzmann transport theory. By comparing with recent experiments, we find that Coulomb-type impurity is dominant scatterer at low temperatures.