First-Principles Study of Structural, Electronic and Thermoelectric Properties of Ni-Doped Bi2Se3

Direct conversion of waste heat to electrical energy could address present energy challenges. Bi2Se3 is one of few thermoelectric materials known to operate at room temperature. Comprehensive analysis using density functional theory was conducted to explore the effect of nickel doping on structural, electronic, and thermoelectric properties of Bi2Se3. Local density approximation (LDA) was used with an addition of spin-orbit coupling (SOC) and van der Waals interaction scheme consideration. Analysis of the effect of SOC was elaborated. It was found that nickel has changed the crystal structure of Bi2Se3. Nickel has also changed band structure and density of state that alter the thermoelectric performance. The decreased band gap has decreased the thermopower. However, it gives advantages to the improvement of electrical conductivity. Higher electrical conductivity has risen thermal conductivity. Despite the decreased thermopower and increased thermal conductivity, the higher electrical conductivity has improved the overall thermoelectric performance of Bi2Se3 when nickel is introduced.