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Title: Investigation of n-type doping strategies for Mg 3Sb 2

Recent, and somewhat surprising, successful n-type doping of Mg 3Sb 2 was the key to realizing high thermoelectric performance in this material. Herein, we use first-principles defect calculations to investigate different extrinsic n-type doping strategies for Mg 3Sb 2 and to reveal general chemical trends in terms of dopant solubilities and maximal achievable electron concentrations. In agreement with experiments, we find that Sb substitution is an effective doping strategy, with Se and Te doping predicted to yield up to ~8 × 10 19 cm –3 electrons. However, we also find that Mg substitution with trivalent (or higher) cations can be even more effective; in particular, the predicted highest achievable electron concentration (~5 × 10 20 cm –3) with La as an extrinsic dopant exceeds that of Se and Te doping. Interstitial doping (Li, Zn, Cu, Be) is found to be largely ineffective either due to self-compensation (Li) or high formation energy (Zn, Cu, Be). Lastly, our results offer La as an alternative dopant to Te and Se and reinforce the need for careful phase boundary mapping in achieving high electron concentrations in Mg 3Sb 2.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [1] ;  [1]
  1. Colorado School of Mines, Golden, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Colorado School of Mines, Golden, CO (United States)
Publication Date:
Report Number(s):
NREL/JA-5K00-72221
Journal ID: ISSN 2050-7488; JMCAET
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Chemistry. A
Additional Journal Information:
Journal Volume: 6; Journal Issue: 28; Journal ID: ISSN 2050-7488
Publisher:
Royal Society of Chemistry
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; defect calculations; dopant solubility; electron concentration; formation energies; general chemicals; high electron concentration; self compensation; thermoelectric performance
OSTI Identifier:
1465656

Gorai, Prashun, Ortiz, Brenden R., Toberer, Eric S., and Stevanović, Vladan. Investigation of n-type doping strategies for Mg3Sb2. United States: N. p., Web. doi:10.1039/C8TA03344G.
Gorai, Prashun, Ortiz, Brenden R., Toberer, Eric S., & Stevanović, Vladan. Investigation of n-type doping strategies for Mg3Sb2. United States. doi:10.1039/C8TA03344G.
Gorai, Prashun, Ortiz, Brenden R., Toberer, Eric S., and Stevanović, Vladan. 2018. "Investigation of n-type doping strategies for Mg3Sb2". United States. doi:10.1039/C8TA03344G.
@article{osti_1465656,
title = {Investigation of n-type doping strategies for Mg3Sb2},
author = {Gorai, Prashun and Ortiz, Brenden R. and Toberer, Eric S. and Stevanović, Vladan},
abstractNote = {Recent, and somewhat surprising, successful n-type doping of Mg3Sb2 was the key to realizing high thermoelectric performance in this material. Herein, we use first-principles defect calculations to investigate different extrinsic n-type doping strategies for Mg3Sb2 and to reveal general chemical trends in terms of dopant solubilities and maximal achievable electron concentrations. In agreement with experiments, we find that Sb substitution is an effective doping strategy, with Se and Te doping predicted to yield up to ~8 × 1019 cm–3 electrons. However, we also find that Mg substitution with trivalent (or higher) cations can be even more effective; in particular, the predicted highest achievable electron concentration (~5 × 1020 cm–3) with La as an extrinsic dopant exceeds that of Se and Te doping. Interstitial doping (Li, Zn, Cu, Be) is found to be largely ineffective either due to self-compensation (Li) or high formation energy (Zn, Cu, Be). Lastly, our results offer La as an alternative dopant to Te and Se and reinforce the need for careful phase boundary mapping in achieving high electron concentrations in Mg3Sb2.},
doi = {10.1039/C8TA03344G},
journal = {Journal of Materials Chemistry. A},
number = 28,
volume = 6,
place = {United States},
year = {2018},
month = {6}
}

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