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Title: 125Te NMR and Seebeck Effect in Bi2Te3 Synthesized from Stoichiometric and Te-Rich Melts

Abstract

Bi2Te3 is a well-known thermoelectric material and, as a new form of quantum matter, a topological insulator. Variation of local chemical composition in Bi2Te3 results in formation of several types of atomic defects, including Bi and Te vacancies and Bi and Te antisite defects; these defects can strongly affect material functionality via generation of free electrons and/or holes. Nonuniform distribution of atomic defects produces electronic inhomogeneity, which can be detected by 125Te nuclear magnetic resonance (NMR). Here we report on 125Te NMR and Seebeck effect (heat to electrical energy conversion) for two single crystalline samples: (#1) grown from stoichiometric composition by Bridgman technique and (#2) grown out of Te-rich, high temperature flux. The Seebeck coefficients of these samples show p- and n-type conductivity, respectively, arising from different atomic defects. 125Te NMR spectra and spin–lattice relaxation measurements demonstrate that both Bi2Te3 samples are electronically inhomogeneous at the atomic scale, which can be attributed to a different Te environment due to spatial variation of the Bi/Te ratio and formation of atomic defects. In conclusion, correlations between 125Te NMR spectra, spin–lattice relaxation times, the Seebeck coefficients, carrier concentrations, and atomic defects are discussed. Our data demonstrate that 125Te NMR is an effective probemore » to study antisite defects in Bi2Te3.« less

Authors:
 [1];  [2];  [1];  [1];  [3];  [1];  [2];  [1];  [2];  [1];  [4]
  1. Ames Lab., Ames, IA (United States). Division of Materials Sciences and Engineering
  2. (United States). Dept. of Physics and Astronomy
  3. Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
  4. (United States). Dept. of Materials Science and Engineering
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1342943
Report Number(s):
IS-J-9117
Journal ID: ISSN 1932-7447
Grant/Contract Number:  
AC02-07CH11358
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 120; Journal Issue: 44; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Levin, E. M., Iowa State Univ., Ames, IA, Riedemann, T. M., Howard, A., Jo, N. H., Bud’ko, S. L., Iowa State Univ., Ames, IA, Canfield, P. C., Iowa State Univ., Ames, IA, Lograsso, T. A., and Iowa State Univ., Ames, IA. 125Te NMR and Seebeck Effect in Bi2Te3 Synthesized from Stoichiometric and Te-Rich Melts. United States: N. p., 2016. Web. doi:10.1021/acs.jpcc.6b06973.
Levin, E. M., Iowa State Univ., Ames, IA, Riedemann, T. M., Howard, A., Jo, N. H., Bud’ko, S. L., Iowa State Univ., Ames, IA, Canfield, P. C., Iowa State Univ., Ames, IA, Lograsso, T. A., & Iowa State Univ., Ames, IA. 125Te NMR and Seebeck Effect in Bi2Te3 Synthesized from Stoichiometric and Te-Rich Melts. United States. doi:10.1021/acs.jpcc.6b06973.
Levin, E. M., Iowa State Univ., Ames, IA, Riedemann, T. M., Howard, A., Jo, N. H., Bud’ko, S. L., Iowa State Univ., Ames, IA, Canfield, P. C., Iowa State Univ., Ames, IA, Lograsso, T. A., and Iowa State Univ., Ames, IA. Fri . "125Te NMR and Seebeck Effect in Bi2Te3 Synthesized from Stoichiometric and Te-Rich Melts". United States. doi:10.1021/acs.jpcc.6b06973. https://www.osti.gov/servlets/purl/1342943.
@article{osti_1342943,
title = {125Te NMR and Seebeck Effect in Bi2Te3 Synthesized from Stoichiometric and Te-Rich Melts},
author = {Levin, E. M. and Iowa State Univ., Ames, IA and Riedemann, T. M. and Howard, A. and Jo, N. H. and Bud’ko, S. L. and Iowa State Univ., Ames, IA and Canfield, P. C. and Iowa State Univ., Ames, IA and Lograsso, T. A. and Iowa State Univ., Ames, IA},
abstractNote = {Bi2Te3 is a well-known thermoelectric material and, as a new form of quantum matter, a topological insulator. Variation of local chemical composition in Bi2Te3 results in formation of several types of atomic defects, including Bi and Te vacancies and Bi and Te antisite defects; these defects can strongly affect material functionality via generation of free electrons and/or holes. Nonuniform distribution of atomic defects produces electronic inhomogeneity, which can be detected by 125Te nuclear magnetic resonance (NMR). Here we report on 125Te NMR and Seebeck effect (heat to electrical energy conversion) for two single crystalline samples: (#1) grown from stoichiometric composition by Bridgman technique and (#2) grown out of Te-rich, high temperature flux. The Seebeck coefficients of these samples show p- and n-type conductivity, respectively, arising from different atomic defects. 125Te NMR spectra and spin–lattice relaxation measurements demonstrate that both Bi2Te3 samples are electronically inhomogeneous at the atomic scale, which can be attributed to a different Te environment due to spatial variation of the Bi/Te ratio and formation of atomic defects. In conclusion, correlations between 125Te NMR spectra, spin–lattice relaxation times, the Seebeck coefficients, carrier concentrations, and atomic defects are discussed. Our data demonstrate that 125Te NMR is an effective probe to study antisite defects in Bi2Te3.},
doi = {10.1021/acs.jpcc.6b06973},
journal = {Journal of Physical Chemistry. C},
number = 44,
volume = 120,
place = {United States},
year = {2016},
month = {10}
}

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