Axis Dependent Transport Properties of Single Crystal Re4Si7

ORAL

Abstract

We measured the thermoelectric transport properties of Re4Si7 along different axis and prove Re4Si7 to have axis dependent carrier polarity. In the cryostat measurement, we observe electrical conductivity and thermopower both increasing with temperature. In-plane Hall effects shows the crystals we obtained has a carrier density around 2*1019/cm3, while the Hall coefficient in-plane and cross-plane have opposite signs. Thermal conductivity measurement shows an isotropic lattice thermal and Nernst measurement shows a small Nernst coefficient and eliminates the possibility of two carrier system. High temperature thermoelectric properties measurement shows the resistivity keeps decreasing at high temperature. The thermopower of the cross-plane direction reaches 300 µV/K and turns flat at high temperature, which may come from a thermal smearing effect. With an estimate of the thermal conductivity, we propose a promising ZT over unity for future optimization.

–

Presenters

  • Bin He

    Ohio State University

Authors

  • Bin He

    Ohio State University

  • Mike Scudder

    Ohio State University

  • Yaxian Wang

    Ohio State University

  • Wolfgang E Windl

    Ohio State University

  • Joshua E. Goldberger

    Ohio State University, Department of Chemistry and Biochemistry, The Ohio 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