Electrical properties of Ca2Si sintered compact synthesized by spark plasma sintering

Single-phase orthorhombic Ca2Si sintered compacts were synthesized by the spark plasma sintering technique. The electronic structures and Seebeck coefficient of Ca2Si were calculated using the first-principles total-energy calculation program. It was found that the Ca2Si compact showed a p-type conductivity of ∼10−2 S/cm with an activation energy of 0.13 eV, and the experimental Seebeck coefficient is larger than 250 μV/K from 373 K to 573 K.