Transport properties of topologically non-trivial bismuth tellurobromides BinTeBr
Falk Pabst, Dean Hobbis, Alzahrani Noha, Hsin Wang, I.P. Rusinov, E.V. Chulkov, Joshua B. Martin, Michael Ruck, George S. Nolas
Temperature dependent transport properties of the recently discovered layered bismuth-rich tellurobromides BinTeBr (n = 2, 3) are investigated for the first time. Dense homogeneous polycrystalline specimens prepared for different electrical and thermal measurements were synthesized by a ball milling-based process. Bi2TeBr is a semiconductor while the additional bismuth layer in the Bi3TeBr crystal structure leads to metallic conduction. The thermal conductivity of the semiconducting compositions is low and the electrical properties are sensitive to doping with a factor of four reduction in resistivity observed at room temperature for only 3% Pb doping. Investigation of the thermoelectric properties suggests that optimization for thermoelectrics may depend on particular elemental substitution. The results presented are intended to expand on the research into tellurohalides in order to further the fundamental investigation of these materials for potential thermoelectric applications.