Thermoelectrics (TE) can be used either for energy harvesting by transforming ambient or waste heat to electric power, or for solid state coolers/heat pumps. The efficiency of TE is characterized by a dimensionless parameter called ZT. For most TE's the room-temperature value of ZT is below unity. The projected market of thermoelectric materials and devices depends exponentially on ZT and is estimated to exceed $10 billion if ZT>2.0 can be achieved at 300K. There are both theoretical and experimental evidences indicating that hydrostatic tensile strain applied to narrow band gap semiconductors composed of heavy chemical elements such as Bi2Te3, PbTe, or PbSe could improve their thermoelectric figure of merit. The goal of this project is therefore to verify this hypothesis through numerical experiments. The first task consists in automatizing the calculation of the electronic bandstructure of the considered semiconductors using a commercial ab-initio tool going beyond the standard Density Functional Theory approximation and including GW corrections. Then, the results should be used in the linearized Boltzmann Transport Equation to evaluate and optimize the ZT parameter of strained Bi2Te3, PbTe, or PbSe. If ZT>2 values are obtained, the work will be published in a journal paper.
- Looking for 1 Master student
- Contact: Mathieu Luisier