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Title: Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe

Abstract

Local thermal magnetization fluctuations in Li-doped MnTe are found to increase its thermopower α strongly at temperatures up to 900 K. Below the Néel temperature ( T N~ 307 K), MnTe is antiferromagnetic, and magnon drag contributes α mdto the thermopower, which scales as ~T 3. Magnon drag persists into the paramagnetic state up to >3 × T N because of long-lived, short-range antiferromagnet-like fluctuations (paramagnons) shown by neutron spectroscopy to exist in the paramagnetic state. The paramagnon lifetime is longer than the charge carrier–magnon interaction time; its spin-spin spatial correlation length is larger than the free-carrier effective Bohr radius and de Broglie wavelength. Thus, to itinerant carriers, paramagnons look like magnons and give a paramagnon-drag thermopower. This contribution results in an optimally doped material having a thermoelectric figure of merit ZT> 1 at T> ~900 K, the first material with a technologically meaningful thermoelectric energy conversion efficiency from a spin-caloritronic effect.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [3];  [2]; ORCiD logo [4]; ORCiD logo [2];  [2];  [2]; ORCiD logo [4]; ORCiD logo [3]; ORCiD logo [1]; ORCiD logo [2]
  1. The Ohio State Univ., Columbus, OH (United States)
  2. Chinese Academy of Sciences (CAS), Beijing (China)
  3. North Carolina State Univ., Raleigh, NC (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
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). Materials Sciences & Engineering Division
OSTI Identifier:
1564212
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 5; Journal Issue: 9; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Zheng, Y., Lu, T., Polash, Md M. H., Rasoulianboroujeni, M., Liu, N., Manley, Michael E., Deng, Y., Sun, P. J., Chen, X. L., Hermann, Raphael P., Vashaee, D., Heremans, J. P., and Zhao, H. Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe. United States: N. p., 2019. Web. doi:10.1126/sciadv.aat9461.
Zheng, Y., Lu, T., Polash, Md M. H., Rasoulianboroujeni, M., Liu, N., Manley, Michael E., Deng, Y., Sun, P. J., Chen, X. L., Hermann, Raphael P., Vashaee, D., Heremans, J. P., & Zhao, H. Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe. United States. doi:10.1126/sciadv.aat9461.
Zheng, Y., Lu, T., Polash, Md M. H., Rasoulianboroujeni, M., Liu, N., Manley, Michael E., Deng, Y., Sun, P. J., Chen, X. L., Hermann, Raphael P., Vashaee, D., Heremans, J. P., and Zhao, H. Fri . "Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe". United States. doi:10.1126/sciadv.aat9461. https://www.osti.gov/servlets/purl/1564212.
@article{osti_1564212,
title = {Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe},
author = {Zheng, Y. and Lu, T. and Polash, Md M. H. and Rasoulianboroujeni, M. and Liu, N. and Manley, Michael E. and Deng, Y. and Sun, P. J. and Chen, X. L. and Hermann, Raphael P. and Vashaee, D. and Heremans, J. P. and Zhao, H.},
abstractNote = {Local thermal magnetization fluctuations in Li-doped MnTe are found to increase its thermopower α strongly at temperatures up to 900 K. Below the Néel temperature (TN~ 307 K), MnTe is antiferromagnetic, and magnon drag contributes αmdto the thermopower, which scales as ~T3. Magnon drag persists into the paramagnetic state up to >3 ×TN because of long-lived, short-range antiferromagnet-like fluctuations (paramagnons) shown by neutron spectroscopy to exist in the paramagnetic state. The paramagnon lifetime is longer than the charge carrier–magnon interaction time; its spin-spin spatial correlation length is larger than the free-carrier effective Bohr radius and de Broglie wavelength. Thus, to itinerant carriers, paramagnons look like magnons and give a paramagnon-drag thermopower. This contribution results in an optimally doped material having a thermoelectric figure of merit ZT> 1 at T> ~900 K, the first material with a technologically meaningful thermoelectric energy conversion efficiency from a spin-caloritronic effect.},
doi = {10.1126/sciadv.aat9461},
journal = {Science Advances},
number = 9,
volume = 5,
place = {United States},
year = {2019},
month = {9}
}

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