Abstract

Thermoelectric materials have the potential to dramatically improve the energy efficiency of many devices and industrial processes by converting waste heat into electricity. An ideal thermoelectric material has high electrical conductivity and low thermal conductivity, requirements which are often in conflict. I will introduce the fundamental physics of thermoelectrics, and how they may be modelled accurately using ab initio quantum mechanical simulations to explain the behaviour of current materials as well as predicting entirely new thermoelectrics.

Once a suitable thermoelectric material has been selected, the standard methods to improve thermoelectric performance usually rely on introducing defects to scatter heat-carrying phonons, yet such defects often scatter the current carriers as well. An alternative approach is to pattern the material at the nanoscale to create a nanophononic metamaterial (NPM), designing the phonon resonances to suppress the lattice thermal conductivity whilst leaving the electronic properties almost unchanged. Designing efficient NPMs calls for challenging, large-scale modelling with the accuracy of ab initio simulations, and I will present new advances in this area. Initial simulations of such NPMs already predict thermoelectric properties far in excess of the corresponding bulk materials, and pave the way for a new generation of cheap, efficient thermoelectric devices.