The introduction of foreign atoms or vacancies into crystal matrices forms atomic-level defects, giving rise to unique defect structures influenced by their coordination preferences and sizes relative to constituent atoms in the matrix. These defects can evolve into more complex structures like one-dimensional dislocations or nanostructures, each interacting uniquely with charge carriers and phonons, thereby significantly impacting the transport properties of bulk solids. Consequently, understanding the formation mechanisms of these defects is essential for developing highly predictable design principles and stabilizing desired defect structures within bulk crystals.

In this presentation, I will discuss our recent research on the deliberate design of multiscale defect structures across various types of crystal lattices. These structures enable independent control over crucial physical parameters that determine the thermoelectric figure of merit (ZT), such as carrier mobility, concentration, electrical conductivity, and Seebeck coefficient. Through this approach, we explore unconventional pathways to enhance ZT, promising significant advancements in thermoelectric materials.