Electrical transport properties of CaMnO3 thermoelectric compound: a theoretical study

highlights•The calculated transport coefficient results confirm its transport anisotropy.•The compound shows higher electrical performance within a and c directions.•The power factor shows sensitive dependence on temperature.•The maximum power factor reaches 8.4×1023 W m−1 K−2 s−1 at 973 K within the c direction.

The electrical transport coefficients of anti-ferromagnetic CaMnO3 have been investigated by density functional theory calculation within generalized gradient approximation. The calculated transport coefficients exhibit the anisotropic nature, in agreement with its electronic states. The transport property results reveal the stronger carrier transport along the O1–Mn–O1 plane within the O–Mn–O octahedron, indicating that the Mnd and O1p orbitals are mainly responsible for electrical transport. The maximum power factor values as a function of relaxation time reach 8.4×1023 Wm−1 K−2 s−1, 7.9×1023Wm−1 K−2 s−1 and 4.9×1023 Wm−1 K−2 s−1 within c, a and b direction, respectively. The dimensionless figure of merit ZTxx, ZTyy as well as ZTzz is estimated with 1.28, 0.8 and 1.37 at 1000 K, respectively.

Graphical abstractThe electrical transport coefficients of anti-ferromagnetic CaMnO3 have been theoretically investigated in detail by means of density functional theory calculation method via analyzing the band structure. The transport property results reveal the stronger carrier transport along the O1–Mn–O1 plane within the O–Mn–O octahedron. The maximum power factor values as a function of relaxation time reach 8.4×1023 W m−1 K−2 s−1, 7.9×1023 W m−1 K−2 s−1 and 4.9×1023 W m−1 K−2 s−1 within c, a and b direction, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide