Microscopic origin of the high thermoelectric figure of merit of n-doped SnSe

Author(s)

Chaves, Anderson S. ^[1] ; Larson, Daniel T. ^[2] ; Kaxiras, Efthimios ^{[2, 3]} ; Antonelli, Alex ^{[1, 4]}

Affiliation

^[1] Univ Estadual Campinas, Gleb Wataghin Inst Phys, POB 13083-859, Campinas, SP - Brazil

^[2] Harvard Univ, Dept Phys, Cambridge, MA 02138 - USA

^[3] Harvard Univ, John A Paulson Sch Engn & Appl Sci, Cambridge, MA 02138 - USA

^[4] Univ Estadual Campinas, Ctr Comp Engn & Sci, POB 13083-859, Campinas, SP - Brazil

• Document type: Journal article
• Source: Physical Review B; v. 104, n. 11 SEP 24 2021.
• Web of Science Citations: 0

Abstract

Excellent thermoelectric performance in the out-of-layer n-doped SnSe has been observed experimentally {[}Chang et al., 160. 778 (2018)]. However, a first-principles investigation of the dominant scattering mechanisms governing all thermoelectric transport properties is lacking. In the present paper, by applying extensive first-principles calculations of electron-phonon coupling associated with parameterized calculation of the scattering by ionized impurities, we investigate the reasons behind the superior figure of merit as well as the enhancement of zT above 600 K in n-doped out-of-layer SnSe, as compared to p-doped SnSe with similar carrier densities. For the n-doped case, the relaxation time is dominated by ionized impurity scattering and increases with temperature, a feature that maintains the power factor at high values at higher temperatures and simultaneously causes the carrier thermal conductivity at zero electric current (k(e1)) to decrease faster for higher temperatures, leading to an ultrahigh-zT = 3.1 at 807 K. We rationalize the roles played by k(el) and K-0 (the thermal conductivity due to carrier transport under isoelectrochemical conditions) in the determination of zT. Our results show the ratio between K-0 and the lattice thermal conductivity indeed corresponds to the upper limit for zT, whereas the difference between calculated zT and the upper limit is proportional to K-e1. (AU)

• FAPESP's process: 19/26088-8 - Study of doping effects in As2Se3 and As2S3 from first-principles calculations
• Grantee: Anderson Silva Chaves
• Support Opportunities: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 16/23891-6 - Computer modeling of condensed matter
• Grantee: Alex Antonelli
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/26105-4 - Multi-user equipment approved in grant 2016/23891-6 high performace computational cluster
• Grantee: Alex Antonelli
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 15/26434-2 - Study of the electronic, structural, and transport properties of materials for thermoelectric applications via ab initio calculations
• Grantee: Anderson Silva Chaves
• Support Opportunities: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 10/16970-0 - Computational modeling of condensed matter: a multiscale approach
• Grantee: Alex Antonelli
• Support Opportunities: Research Projects - Thematic Grants