Paramagnon drag yields a high thermoelectric figure of merit in Li-doped MnTe

ORAL

Abstract

MnTe is an antiferromagnetic semiconductor with a Neel temperature of 307 K. In the antiferromagnet phase, the magnon-electron interaction gives rise to a magnon-drag contribution to thermopower. Surprisingly this magnon-drag thermopower extends to the paramagnetic phase. Experimental results provide evidence for the effect of locally ordered thermal fluctuations of magnetization with finite lifetime (paramagnons). When the lifetime of the paramagnons is longer than the electron-paramagnon scattering time, the paramagnons can effectively push the electrons and contributes to thermoelectric power. By analyzing the measured thermopower, resistivity, Hall coefficient, specific heat and magnetization, a quantitative explanation is given for thermopower of both the AFM and PM regime based upon the hydrodynamic theory [1]. As a result, the ZT of the best sample exceeds 1 at 950 K.

*YZ and JPH acknowledge the ARO MURI under grant number W911NF-14-1-0016. DV acknowledges partial support by Air Force Office of Scientific Research (AFOSR) under contract number FA9550-12-1-0225 and the National Science Foundation (NSF) under grant numbers ECCS-1351533, and CMMI-1363485.

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Presenters

  • Yuanhua Zheng

    • Department of Mechanical and Aerospace Engineering, The Ohio State University
    • Ohio State University

Authors

  • Yuanhua Zheng

    • Department of Mechanical and Aerospace Engineering, The Ohio State University
    • Ohio State University

  • Tianqi Lu

    • Chinese Academy of Sciences, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics
    • Institute of Physics, Chinese Academy of Sciences

  • Md Mobarak Hossain Polash

    • Department of Materials Science and Engineering, North Carolina State University
    • North Carolina State University

  • Morteza Rasoulianboroujeni

    • Department of Developmental Science, Marquette University
    • North Carolina State University

  • Ning Liu

    • Chinese Academy of Sciences, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics
    • Institute of Physics, Chinese Academy of Sciences

  • Michael Manley

    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge TN-37831-6064, USA

  • Yuan Deng

    • Beihang University

  • Peijie Sun

    • Institute of Physics, Chinese Academy of Sciences

  • Xiaolong Chen

    • Institute of Physics, Chinese Academy of Sciences

  • Raphael Hermann

    • Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge TN-37831-6064, USA

  • Daryoosh Vashaee

    • Department of Electrical and Computer Engineering, North Carolina State University
    • North Carolina State University

  • Joseph P C Heremans

    • Department of Mechanical and Aerospace Engineering, The Ohio State University
    • Ohio State University
    • Ohio State Univ - Columbus
    • Department of Mechanical Engineering, The Ohio State University
    • Department of Mechanical and Aerospace Engineering, Department of Physics, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA

  • Huaizhou Zhao

    • Institute of Physics, Chinese Academy of Sciences
    • Chinese Academy of Sciences, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics
    • Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China