Structural complexity can lead towards materials with low thermal conductivities (κ) – one of the key requirements for efficient thermoelectric and phase change materials. In polar chalcogenides and pnictides, asymmetric coordination environments and complex structural motifs, e.g. polyanionic networks, layers or channels can be obtained through a charge transfer from the cation to the anionic framework and through the formation stereoactive lone pairs. By including transition metals interesting magnetic properties such as spin frustration or mixed valence can arise and sharp features in the electronic density of states can be introduced close to the Fermi level influencing electronic structure and physical properties.
Several examples of complex compounds will exemplify our work towards a better understanding of the relation between bonding and properties in these rich families of intermetallics.