Ab initio prediction of thermoelectric properties of monolayer ZrNCl and HfNCl

• Published in: Journal of solid state chemistry Vol. 290; p. 121500
• Main Authors: Liu, Xinyu, An, Xiaoning, Xu, Bin, Xia, Qiong, Lu, Guiming, Yu, Gongqi, Zhang, Jing, Ma, Shanshan, Wang, Yusheng, Li, Jifang, Dong, Hongbing, Yi, Lin
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.10.2020
• Subjects: Boltzmann transport theory; Density functional theory; Monolayer ZrNCl and HfNCl; Thermoelectric transport properties; Density functional theory; Monolayer ZrNCl and HfNCl; Boltzmann transport theory; Thermoelectric transport properties
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2020.121500

Layered materials are generally considered to be good candidates for thermoelectric materials, and the monolayer ZrNCl and HfNCl obtained from layered material ZrNCl and HfNCl should have lower lattice thermal conductivity. Here the electronic structure and thermoelectric properties of monolayer ZrNCl and HfNCl are studied by the first principles and the semi-classical Boltzmann theory. It is found that the DOS of HfNCl is larger than that of ZrNCl near Fermi surface, which shows that Seebeck coefficient of HfNCl are also larger than that of ZrNCl. The high frequency of the acoustic branch of HfNCl is relatively low, therefore, the lattice thermal conductivity of HfNCl is lower. The electrical conductivity of HfNCl is larger than that of ZrNCl. Therefore, HfNCl have good thermoelectric transport performance and high thermoelectric optimal value. ZT as a function of temperature for monolayer ZrNCl (Left) and monolayer HfNCl (Right). The Seebeck coefficient and electrical conductivity of HfNCl is larger than that of ZrNCl, nevertheless the lattice thermal conductivity of HfNCl is smaller than that of ZrNCl. Therefore, HfNCl have good thermoelectric transport performance and high thermoelectric optimal value. [Display omitted] •Seebeck coefficient of HfNCl are also larger than that of ZrNCl.•High frequency of acoustic branch of HfNCl causes lower lattice thermal conductivity.•The electrical conductivity of HfNCl is larger than that of ZrNCl.•HfNCl have good thermoelectric transport performance.