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This content will become publicly available on January 30, 2019

Title: Theoretical investigations of electrical transport properties in CoSb3 skutterudites under hydrostatic loadings

We report that CoSb 3-based skutterudites have been a benchmark mid-temperature thermoelectric material under intensive experimental and theoretical studies for decades. Doping and filling, to the first order, alter the crystal lattice constant of CoSb 3 in the context of “chemical pressure.” In this work, we employed ab initio density functional theory in conjunction with semiclassical Boltzmann transport theory to investigate the mechanical properties and especially how hydrostatic loadings, i.e., “physical pressure,” impact the electronic band structure, Seebeck coefficient, and power factor of pristine CoSb 3. It is found that hydrostatic pressure enlarges the band gap, suppresses the density of states (DOS) near the valence band edge, and fosters the band convergence between the valley bands and the conduction band minimum (CBM). By contrast, hydrostatic tensile reduces the band gap, increases the DOS near the valence band edge, and diminishes the valley bands near the CBM. Therefore, applying hydrostatic pressure provides an alternative avenue for achieving band convergence to improve thermoelectric properties of N-type CoSb 3, which is further supported by our carrier concentration studies. Lastly, these results provide valuable insight into the further improvement of thermoelectric performance of CoSb 3-based skutterudites via a synergy of physical and chemical pressures.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ; ORCiD logo [5] ;  [5] ; ORCiD logo [6] ; ORCiD logo [6]
  1. Clemson Univ., SC (United States). Department of Mechanical Engineering; Univ. of Minnesota-Twin Cities, Minneapolis, MN (United States). Department of Mechanical Engineering
  2. Montgomery High School, Skillman, NJ (United States)
  3. Univ. of Minnesota-Twin Cities, Minneapolis, MN (United States). Department of Mechanical Engineering
  4. Clemson Univ., SC (United States). Department of Mechanical Engineering
  5. Clemson Univ., SC (United States). Department of Physics and Astronomy
  6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences and Computational Sciences and Engineering Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Rare Metals
Additional Journal Information:
Journal Volume: 37; Journal Issue: 4; Journal ID: ISSN 1001-0521
Publisher:
Nonferrous Metals Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; CoSb3 skutterudite; Hydrostatic loadings; Mechanical properties; Electronic structure; Seebeck coefficient; Thermoelectrics
OSTI Identifier:
1422569