Supervisors: Phytos Neophytou; Julie Staunton

Summary:
Recent advances from condensed matter physics have highlighted a new class of materials whose atomic geometries profoundly affect the nature of their electronic states. The study of these materials has the potential to revolutionize electronics, spintronics, and energy harvesting. Motivated by recent extraordinary experimental measurements and theoretical predictions, this project will investigate the thermoelectric performance of these so-called `topological’ materials, i.e. their ability to convert heat into electricity. The project merges physics and materials engineering, and utilizes DFT and state-of-the-art electronic transport methods. These materials exhibit novel electronic properties with indications for an unprecedented 10-fold performance increase. There is the prospect of constituting the ultimate thermoelectric energy-harvesting materials, with enormous contribution to energy savings and net-zero sustainability.

Background:
The need for energy sustainability and the environmental consequences of fossil fuels make the development of technologies for clean energy generation imperative. Thermoelectric (TE) materials can harvest enormous amounts of waste heat and convert it into useful electrical power. As 60% of all energy we use is lost into heat during conversion processes, the realization of efficient and scalable TEs can transform the energy-use/savings landscape and play a major role in net-zero sustainability. However, TEs have not found widespread use because of low material efficiencies.

Recently, advancements in condensed matter physics have realized the new class of the so-called ‘topological’ materials, with the potential to revolutionize electronics, spintronics, and energy harvesting. These are materials with their electronic band structures consisting of novel features, leading to novel electronic properties. These allow simultaneously many effects advantageous for TEs, some of which are not encountered in common materials. Most important are the linear dispersions with ballistic, dissipation-less electronic transport even at room temperature (rather than the diffusive transport encountered in traditional TEs). Experiments have already demonstrated the potential for an unprecedented 10-fold increase in performance, highlighting the prospect that topological materials could constitute the ultimate TEs.

The project merges physics and materials engineering, and utilizes DFT and state-of-the-art electronic transport methods. It uses theory and large-scale simulation to investigate the electronic and thermoelectric properties of novel topological materials and alloys, and identify the electronic structure features that optimize their performance. A variety of electronic transport methods (semiclassical and quantum mechanical), as well as a variety of electronic structure methods (DFT, low energy k.p, tight-binding) will be utilized appropriately in a multi-physics, multi-scale methodology. The targeted applications are not limited to energy harvesting, but extend to the field of spintronics and quantum electronics.