Topological Phonons and Thermoelectric Conversion in Crystalline Materials

Abstract

Topological phononics, a fascinating frontier in condensed matter physics, holds great promise for advancing energy‐related applications. Topologically nontrivial phonons typically possess gapless edge or surface states. These exotic states of lattice vibrations, characterized by their nontrivial topology, offer unique opportunities for manipulating and harnessing energy transport. The exploration of topological phonons opens new avenues in understanding and controlling thermal transport properties, with potential applications in fields such as thermoelectric materials, phononic devices, and waste heat recovery. Here, an overview of concepts such as Berry curvature and topological invariants, along with the applications of phonon tight‐binding method and nonequilibrium Green's function method in the field of topological phononics is provided. This review encompasses the latest research progress of various topological phonon states within crystalline materials, including topological optical phonons, topological acoustical phonons, and higher‐order topological phonons. Furthermore, the study delves into the prospective applications of topological phonons in the realm of thermoelectric conversion, focusing on aspects like size effects and symmetry engineering.

Machine learning assisted understanding of the layer-thickness dependent thermal conductivity in fluorinated graphene

“…Yuan et al [23] emphasized the complex relationship between atomic mass, bonding characteristics, and thermal performance through their analysis of Janus XBAlY (X = Se, S, Te, Y = S, Se, O, X ̸ = Y) monolayers. Ding et al [24] by exploring topological phonons, have opened up new avenues for understanding and controlling thermal transport properties, with potential applications in thermoelectric materials, phononic devices, and waste heat recovery. By analyzing the κ of 2D materials, Gu et al [25] found that the high thermal yield materials have plane structure, and the medium κ materials have three-layer mirror symmetrical crystal structure, low κ materials have double-layer or three-layer crystal structure, but no mirror symmetry, which indicates that the κ of 2D materials is highly sensitive to crystal structure.…”

GaInX3 (X = S, Se, Te): Ultra-low thermal conductivity and excellent thermoelectric performance

“…[20,21] Searching for materials with intrinsically low lattice thermal conductivity is another avenue to obtain high TE performance materials [22,23] because this approach helps to simplify complex TE parameters and optimize TE performance. Due to their unique physical structures, low-dimensional materials possess a variety of physical properties, [24][25][26][27][28][29][30] which provides new possibilities for achieving low thermal conductivity and high TE performance. For instance, the material SnSe exhibits a high TE figure of merit as a result of its low thermal conductivity, while the half-Heusler compound PCdNa is noteworthy for its low thermal conductivity coupled with superior TE performance.…”