Understanding origin, effects and implications of thermal transport is of great interest for applications like energy devices and thermal management of electronics. The main control parameter of thermal transport is thermal conductivity of material, originating from scattering of phonons with different sources. By first principles density functional theory and Boltzmann transport theory we provide an explanation about the origin of striking variation of κ_latt and its anisotropy in group-IV (Zr and Hf) and group-VI (Mo and W) TMDs. The lower thermal conductivity of group IV TMDs is substantiated by 4 times larger Grüneisen parameter (γ) and twice as large anharmonic scattering rate (Wanhar) as compared to the group-VI TMDs. The Born effective charges, which are very different for two class of materials, are the driving factor of this phenomena, as it quantifies interlayer van der Waals (vdW) interaction strengths. We report for the first time an inverse correlation between the strength of vdW interaction and anisotropy in thermal conductivity of these TMDs.

Decoupling the interdependence of electronic and thermal transport has been achieved by utilizing different cationic sites present in cubic spinel oxides. Electronic transport is influenced by the tetrahedrally coordinated atomic sites, whereas thermal transport is by the octahedrally coordinated atomic sites. Making use of this insight, CdCo2O4 material is proposed to have significantly high thermoelectric performance.

Our recent review article on thermoelectrics provides an overview of a wide plethora of thermoelectrics driven by several emerging concepts yet to be explored. Collectively unveiling the key approaches via structures, physics, and chemistry of materials to achieve superior energy conversion efficiency. Tuning crystal structures by varying dimensionality, controlling defect chemistry, and modifying atomic ordering in materials depict an effective breakthrough in designing next-generation thermoelectric materials. A broad overview of the advanced approaches provides guidance in designing new thermoelectric materials.