Large thermal conductivity decrease in point defective Bi2Te3 bulk materials and superlattices

Defective Bi2Te3 structures have been studied with the aim of lowering the thermal conductivity in order to improve the thermoelectric figure of merit. The cross-plane thermal conductivities of structures containing point defects have been computed by means of molecular dynamics techniques, finding a maximum decrease of 70% for a 4% concentration of tellurium atom vacancies. Superlattices with modified stoichiometries have also been considered in order to find the configuration having the lowest thermal conductivity. In this case, a maximum decrease of 70% was also found. These predictions open the way to the design of efficient bulk thermoelectric materials having optimised thermal properties similar to those of superlattices. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4772783]