Band engineering and rational design of high-performance thermoelectric materials by first-principles

Understanding and manipulation of the band structure are important in designing high-performance thermoelectric (TE) materials. Our recent work has involved the utilization of band structure in various topics of TE research, i.e., the band convergence, the conductive network, dimensionality reduction by quantum effects, and high throughput material screening. In non-cubic chalcopyrite compounds, we revealed the relations between structural factors and band degeneracy, and a simple unity-η rule was proposed for selecting high performance diamond-like TE materials. Based on the deep understanding of the electrical and thermal transport, we identified the conductive network in filled skutterudites with the “phonon glass-electron crystal” (PGEC) paradigm, and extended this concept to caged-free Cu-based diamond-like compounds. By combining the band structure calculations and the Boltzmann transport theory, we conducted a high-throughput material screening in half-Heusler (HH) systems, and several promising compositions with high power factors were proposed out of a large composition collection. At last, we introduced the Rashba spin-splitting effect into thermoelectrics, and its influence on the electrical transport properties was discussed. This review demonstrated the importance of the microscopic perspectives for the optimization and design of novel TE materials.

We demonstrate the utilization of band structure in varieties of topics in TE research, including the band convergence, the conductive network, dimensionality reduction by quantum effects, and high throughput material screening. Combining first-principles calculations and Boltzmann transport theory, a new strategy is introduced to design high-performance non-cubic thermoelectric (TE) materials through the utilization of a rational pseudocubic structure that results into cubic-like degenerate electronic bands. Based on the concept of conductive network, we propose the optimization scheme for both electrical and thermal transport properties in caged filled skutterudites and caged-free Cu-based diamond-like compounds. Through the high throughput screening method, several promising half-Heusler compositions with high power factors are proposed out of a large composition collection. At last, we enhance electrical transport by introducing a new spin-orbit splitting effect–the Rashba spin splitting effect.Figure optionsDownload as PowerPoint slide