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Title: Thermoelectric study of crossroads material MnTe via sulfur doping

Here, we report thermoelectric study of crossroads material MnTe via iso-electronic doping S on the Te-site. MnTe{sub 1-x}S{sub x} samples with nominal S content of x = 0.00, 0.05, and 0.10 were prepared using a melt-quench method followed by pulverization and spark plasma sintering. The X-ray powder diffraction, scanning electron microscopy, and ZAF-corrected compositional analysis confirmed that S uniformly substitutes Te up to slightly over 2%. A higher content of S in the starting materials led to the formation of secondary phases. The thermoelectric properties of MnTe{sub 1-x}S{sub x} samples were characterized by means of Seebeck coefficient, electrical conductivity, and thermal conductivity measurements from 300 K to 773 K. Furthermore, Hall coefficient measurements and a single parabolic band model were used to help gain insights on the effects of S-doping on the scattering mechanism and the carrier effective mass. As expected, S doping not only introduced hole charge carriers but also created short-range defects that effectively scatter heat-carrying phonons at elevated temperatures. On the other hand, we found that S doping degraded the effective mass. As a result, the ZT of MnTe{sub 0.9}S{sub 0.1} was substantially enhanced over the pristine sample near 400 K, while the improvement of ZT became marginal at elevated temperatures. Amore » ZT ∼ 0.65 at 773 K was obtained in all three samples.« less
Authors:
; ; ;  [1] ;  [1] ;  [2] ;  [3] ; ;  [4] ;  [1] ;  [5]
  1. Empa–Swiss Federal Laboratories for Materials Science and Technology, Solid State Chemistry and Catalysis, Uberlandstrasse 129, CH-8600 Dübendorf (Switzerland)
  2. (Switzerland)
  3. Institute for Materials Science, University of Stuttgart, DE-70569 Stuttgart (Germany)
  4. Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634-0978 (United States)
  5. (Germany)
Publication Date:
OSTI Identifier:
22277870
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHARGE CARRIERS; EFFECTIVE MASS; ELECTRIC CONDUCTIVITY; GAIN; HOLES; MANGANESE TELLURIDES; PHONONS; SCANNING ELECTRON MICROSCOPY; SINTERING; SULFUR; THERMAL CONDUCTIVITY; THERMOELECTRIC PROPERTIES; X-RAY DIFFRACTION