@article{Liu2024, 
author = {Yifei Liu and Tian-Ran Wei and Jiangtao Wu and Hexige Wuliji and Haoran Huang and Zhengyang Zhou and Kunpeng Zhao and Jie Ma and Xun Shi},
title = {Non-layered InSe nanocrystalline bulk materials with ultra-low thermal conductivity},
year = {2024},
journal = {Journal of Materiomics},
volume = {10},
number = {2},
pages = {448-455},
keywords = {Monoclinic InSe, Chemical bond, Nano grains, Thermal transport},
url = {https://www.sciopen.com/article/10.1016/j.jmat.2023.07.006},
doi = {10.1016/j.jmat.2023.07.006},
abstract = {Exploring new prototypes for a given chemical composition is of great importance and interest to several disciplines. As a famous semiconducting binary compound, InSe usually exhibits a two-dimensional layered structure with decent physical and mechanical properties. However, it is less noticed that InSe can also adopt a monoclinic structure, denoted as mcl-InSe. The synthesis of such a phase usually requires high-pressure conditions, and the knowledge is quite scarce on its chemical bonding, lattice dynamics, and thermal transport. Here in this work, by developing a facile method combining mechanical alloying and spark plasma sintering, we successfully synthesize mcl-InSe bulks with well-crystallized nanograins. The chemical bonding of mcl-InSe is understood as compared with layered InSe via charge analysis. Low cut-off frequencies of acoustic phonons and several low-lying optical modes are demonstrated. Noticeably, mcl-InSe exhibits a low room-temperature thermal conductivity of 0.6 W·m−1·K−1, which is smaller than that of other materials in the In–Se system and many other selenides. Low-temperature thermal analyses corroborate the role of nanograin boundaries and low-frequency optical phonons in scattering acoustic phonons. This work provides new insights into the non-common prototype of the InSe binary compound with potential applications in thermoelectrics or thermal insulation.}
}