Ferroelectric control of nanoscale Electric and Thermal conduction in GeTe – FETh

Thermoelectricity is considered a promising clean energy technology that could help to reduce our dependence on fossil energies by directly and reversibly converting heat into electricity. Achieving a high thermoelectric figure of merit is a major objective to reach a wider use of this technology. So far, thermoelectrics have been optimized via (i) increasing the electrical conductivity by creating energy states close to the Fermi level and (ii) decreasing the thermal conductivity, using defects or nanoscale structures. Nevertheless, the performance gains obtained are low and require new approaches to be considered. In particular, ferroelectric alloys based on germanium telluride have recently shown thermoelectric performances that are comparable to the best known materials. Moreover, it has been theoretically predicted that the thermoelectric performance of ferroelectric domain walls is much higher than that of the bulk of the material. We therefore propose a new paradigm where thermoelectric properties could be controlled at the nanoscale by the ferroelectric domain structure. The ambition of the project is to realize and study ferroelectric domain structures in germanium telluride thin films realized on silicon and on silicon-on-insulator in order to achieve significant advances in terms of thermoelectric performances via materials engineering and the development of advanced experimental characterization methods.