Thermoelectric Performance of Cr Doped and Cr-Fe Double-Doped Higher Manganese Silicides with Adjusted Carrier Concentration and Significant Electron-Phonon Interaction

Quansheng Guo; Wenhao Zhang; Zihang Liu; Xiuwei Fu; Sylvain Le Tonquesse; Naoki Sato; Hyoung-Won Son; Kiyoshi Shimamura; David Berthebaud; Takao Mori

doi:10.1021/acsami.0c21484

Thermoelectric Performance of Cr Doped and Cr-Fe Double-Doped Higher Manganese Silicides with Adjusted Carrier Concentration and Significant Electron-Phonon Interaction

ACS Appl Mater Interfaces. 2021 Feb 24;13(7):8574-8583. doi: 10.1021/acsami.0c21484. Epub 2021 Feb 9.

Authors

Quansheng Guo^{1

2}, Wenhao Zhang^{1

3}, Zihang Liu¹, Xiuwei Fu⁴, Sylvain Le Tonquesse², Naoki Sato¹, Hyoung-Won Son^{1

3}, Kiyoshi Shimamura^{4

5}, David Berthebaud², Takao Mori^{1

3}

Affiliations

¹ WPI Center for Materials Nanoarchitechtonics (WPI-MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba 305-0044, Japan.
² CNRS-Saint Gobain-NIMS, UMI 3629, Laboratory for Innovative Key Materials and Structures (LINK), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba 305-0044, Japan.
³ Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba 305-8671, Japan.
⁴ Optical Single Crystals Group, Research Center for Functional Materials, NIMS, Namiki 1-1, Tsukuba 305-0044, Japan.
⁵ Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo 169-8555, Japan.

PMID: 33560843
DOI: 10.1021/acsami.0c21484

Abstract

Polycrystalline higher manganese silicides Mn_1-xCr_xSi_1.74 (x = 0, 0.10, 0.20) with Cr single doping and Mn_1-2yCr_yFe_ySi_1.74 (y = 0.10, 0.20) with Cr-Fe double doping have been prepared by arc melting and spark plasma sintering. Hall effect results and thermoelectric transport properties measurements demonstrate that Cr doping effectively increases the carrier concentration, thereby giving rise to enhanced electrical conductivity and power factor. Coupled with an enlarged effective mass and a reduction in the lattice thermal conductivity, a maximum zT is realized in Mn_0.90Cr_0.10Si_1.74. It is also proved that the carrier concentration and carrier scattering mechanism could be altered through further doping on the Mn site by Fe, which leads to a lower electrical conductivity and higher Seebeck coefficient. Factors related to the suppression of the lattice thermal conductivity, like mass and strain field fluctuation scattering and electron-phonon scattering, are also analyzed. This work reveals the effects of Cr single doping and Cr-Fe dual-element doping on the carrier concentration, carrier scattering mechanism, and lattice thermal conductivity of higher manganese silicides.

Keywords: carrier concentration; electron−phonon scattering; higher manganese silicides; lattice thermal conductivity; thermoelectrics.