Executive Summary : | Energy waste is primarily used as heat and thermoelectric (TE) materials, which can convert heat into electricity without harmful gas emissions or moving parts. However, the challenge lies in achieving low thermal conductivity and high carrier mobility in a single material. Topological quantum materials (TQMs) have gained attention for their potential applications in TE energy conversion. Homologous series of TQMs, such as (A2)m(A2X3)n and MmQ2Te3n+m, are semiconding in bulk with metallic surface states due to strong spin-orbit coupling. These materials exhibit diverse properties and phenomena, and bridging these fields is appealing. Understanding chemical bonding, electronic band, phonon dispersion, and their correlation with TE transport properties will advance the discovery of novel TQMs for energy conversion. Metavalent bonding, a unique bonding between metallicity and covalency, is predicted to form a bridge between metallicity and covalency, providing advantageous properties for thermoelectric applications. This project proposes different classes of homologous series of TQMs to achieve high thermoelectric performance and uncovers the hidden chemical bonding aspect to understand the origin of different transport properties, including low thermal conductivity and intriguing electronic transports in these rarely investigated compounds. |