FWF - I 623-N16: TQM

Funding institution:
FWF Austrian Science Fund

Project leader:

Silke BÜHLER-PASCHEN

Project duration:

April 2011 - October 2015

THERMOELECTRICITY OF QUANTUM MATTER (TQM)

The discovery of thermoelectricity - the interdependence of an electric field and a temperature gradient in a solid - is almost two centuries old. But our understanding of the basic microscopic physics behind thermoelectric phenomena is still too sketchy to yield an accurate quantitative description of the thermoelectric response and its temperature and field dependence even in simple metals. As a consequence, the quest for useful thermoelectric materials has been mostly an empiric one. A recent surge in this quest, partly motivated by the environment-friendliness of thermoelectric refrigerators and generators, is visible across the worldwide scientific community. From the fundamental point of view, during the last decade, thermoelectricity has proved to be a very sensitive, even if poorly understood, probe of electron organization in solids, in particular in the context of electron correlation.

Thermoelectricity of quantum materials is largely unexplored. There are technical reasons for this. Nowadays, commercial instruments permit to measure the electrical resistivity or specific heat of materials in wide temperature ranges, with high resolution. Accurate low-temperature and high-field measurements of the Seebeck and the Nernst effect, and of the thermal conductivity, however, require a level of experimental sophistication well beyond what is commercially available.

The two partners are among a handful of leading groups on the international scene exploring the thermoelectric response of correlated electrons under extreme conditions. The aim of this project is to initiate a new collaboration in order to carry out high-resolution thermoelectric measurements in a number of quantum materials.

Experimentally ambitious, the scientific scope of the proposal covers a number of issues which are at the heart of the physics of correlated electrons: Quantum criticality in heavy fermion compounds and in graphite, the residual electronic density of states in Kondo insulators and possible relations to metallic surface states of topological insulators, and semimetals pushed beyond the quantum limit. The results are expected to provide fresh experimental input for a deeper theoretical understanding of electronic correlations and thermoelectric phenomena, and ultimately for advancing the field of thermoelectric and thermomagnetic refrigeration.