Electronic structures and thermoelectric properties of La or Ce-doped Bi2Te3 alloys from first principles calculations

Thermoelectric properties of La or Ce-doped Bi2Te3 alloys were systematically investigated by ab initio calculations of electronic structures and Boltzmann transport equations. The Seebeck coefficient of p-type LaBi7Te12 and La2Bi6Te12 was larger than that of Bi2Te3, because La doping increased the effective mass of carriers. On the other hand, the electrical conductivity of LaBi7Te12 and La2Bi6Te12 decreased, which caused a reduction of power factor of these La-doped Bi2Te3 alloys in comparison with Bi2Te3. The influence of Ce doping on the band structure and thermoelectric properties of Bi2Te3 was similar to that of La doping. The theoretical calculation provided an insight into the transport properties of La or Ce-doped Bi2Te3-based thermoelectric materials.