Chin. Phys. B, 2021, Vol. 30(3): 037304    DOI: 10.1088/1674-1056/abd163
Special Issue: SPECIAL TOPIC — Phononics and phonon engineering
 SPECIAL TOPIC—Phononics and phonon engineering Prev   Next

# Enhanced thermoelectric properties in two-dimensional monolayer Si2BN by adsorbing halogen atoms

Cheng-Wei Wu(吴成伟)1, Changqing Xiang(向长青)2, Hengyu Yang(杨恒玉)1, Wu-Xing Zhou(周五星)1,†, Guofeng Xie(谢国锋)1, Baoli Ou(欧宝立)1, and Dan Wu(伍丹)3,
1 School of Materials Science and Engineering & Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, Hunan University of Science and Technology, Xiangtan 411201, China; 2 College of Information Science and Engineering, Jishou University, Jishou 416000, China; 3 School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114, China
Abstract  Using the first principles calculation and Boltzmann transport theory, we study the thermoelectric properties of Si2BN adsorbing halogen atoms (Si2BN-4X, $X=\textF$, Cl, Br, and I). The results show that the adsorption of halogen atoms can significantly regulate the energy band structure and lattice thermal conductivity of Si2BN. Among them, Si2BN-4I has the best thermoelectric performance, the figure of merit can reach 0.50 K at 300 K, which is about 16 times greater than that of Si2BN. This is because the adsorption of iodine atoms not only significantly increases the Seebeck coefficient due to band degeneracy, but also rapidly reduces the phonon thermal conductivity by enhancing phonon scattering. Our work proves the application potential of Si2BN-based crystals in the field of thermoelectricity and the effective method for metal crystals to open bandgaps by adsorbing halogens.
Keywords:  density functional theory      thermoelectric effects      transport properties      electronic structure
Received:  30 September 2020      Revised:  04 December 2020      Accepted manuscript online:  08 December 2020
 PACS: 71.15.-m (Methods of electronic structure calculations) 73.50.Lw (Thermoelectric effects) 74.25.F- (Transport properties) 74.25.Jb (Electronic structure (photoemission, etc.))
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos. 12074115, 11874145, and 51775183) and the Hunan Provincial Natural Science Fund of China (Grant No. 2018JJ2125).
Corresponding Authors:  Corresponding author. E-mail: wuxingzhou@hnu.edu.cn Corresponding author. E-mail: danwu@csust.edu.cn