Thermoelectric properties of A-site substituted Lanthanide Ca0.75R0.25MnO3

Abstract

We present the electronic structure and thermoelectric properties of doped and intrinsic CaMnO3 investigated by first principles and semi-classic Boltzmann theory. The G-type anti-ferromagnetic phase is most stable among five intrinsic anti-ferromagnetic phases, however, the C-type phase is most stable phase after Lanthanides doping in A-site of CaMnO3. Electrons transfer from Lanthanides to Mn d orbital in 25% Lanthanides doped materials, which result in part of conductive bands are occupied by Mn d electrons. The electron transport changes from semiconductor (intrinsic) to metal (doped), this change can be found in Seebeck coefficient and electrical conductivity as the function of temperature. The electrical conductivity is enhanced by Lanthanides doping, and about 2 orders of magnitudes higher than those of intrinsic CaMnO3. So the Lanthanides doping is useful method to modify thermoelectric properties of CaMnO3.