Perspectives on Thermoelectricity in Layered and 2D Materials

Layered materials have garnered immense interest due to their unique electronic, mechanical, thermal, and optoelectronic properties. In these materials, atomically thin layers are held together by van der Waals (vdW) interactions, allowing single layers to be isolated and studied as 2D materials. New theoretical insights as well as novel experimental techniques have empowered recent developments in both thermoelectric physics and performance of 2D materials. In this Review, some of the key ideas are surveyed and open questions are discussed, laying out a vision for original discoveries in this still-emerging field of applied physics. Here, graphene, transition metal dichalcogenides, black phosphorus, topological insulators as well as intercalated compounds are in focus. With these materials as a platform, how band structure, hydrodynamics, metal-insulator transitions, anisotropy, and surface states affect phonons and electrons and manifest in their thermoelectric properties is analyzed.