Strategies and challenges of high-pressure methods applied to thermoelectric materials

We describe the current state of experimental studies of the effects of applied high pressure or stress on the thermoelectric properties and performance parameters of thermoelectric materials, as well as the challenges faced in this area and possible directions for future work. We summarize and analyze literature data on the effects of high pressure on the Seebeck coefficient (thermoelectric power) of different materials that are related to common families of thermoelectrics, such as Bi2Te3, Sb2Te3, Bi2Se3, PbTe, PbSe, SnTe, SnSe, Mg2Si, CoSb3, Si–Ge, and others, or that show promise as potential high-pressure thermoelectrics, such as ZrSe3 and Sn2P2Se6, and others. We consider how applied high pressure or stress can tune the performance parameters of thermoelectric materials through variations in their Seebeck coefficients and in their electrical and thermal conductivities. We point out the potential use of magnetic fields to generate significant transverse and longitudinal magneto-thermoelectric effects in thermoelectric materials, thereby affecting their performance parameters. We propose simple models of high-pressure thermoelectric converters whose performance parameters can be optimized by varying the pressure applied to their elements. We also discuss other possible ways in which high-pressure effects could be implemented in practical appliances.