Doping induced electronic structure and estimated thermoelectric properties of CaMnO3 system

The electronic properties of Sr doped CaMnO3 are studied using the first principle density functional theory calculation based on a plane wave basis and pseudopotentials. The thermoelectric properties are analyzed on the basis of electronic properties. The band structure results show that the doped system undergoes a semiconductor-to-conductor transition and the bands near Fermi level experience a significant distortion; the density of states results show that the density of states near Fermi level is increased. The combination of Mnd and Op orbitals exhibits enhanced covalence nature. It is estimated that the thermopower and carrier conduction capability should be enhanced, and the phonon conduction should be depressed, indicating the improved thermoelectric properties for Sr doped CaMnO3 system.

Research highlights
► The energy band gap of the Sr doped system is narrowed, it is indicated that the system undergoes a semiconductor-to-conductor transition.
► The bands near Fermi level are significantly distorted, combinations of heavy and light carriers are found, this would favor enhanced thermopower.
► The density of states near Fermi level is increased, and the combination of Mnd and Op orbitals exhibit enhanced covalence nature, favored thermoelectric property can be inferred.
► The thermopower and carrier conduction capability should be enhanced, and the phonon conduction should be depressed, these indicate the improved thermoelectric properties for Sr doped CaMnO3 system.