Zou Tianhua, Jia Tiantian, Xie Wenjie, Zhang Yongsheng, Widenmeyer Marc, Xiao Xingxing, Weidenkaff Anke
Institute for Materials Science, University of Stuttgart, 70569 Stuttgart, Germany.
Phys Chem Chem Phys. 2017 Jul 19;19(28):18273-18278. doi: 10.1039/c7cp02744c.
Doping (or substitution)-induced modification of the electronic structure to increase the electronic density of states (eDOS) near the Fermi level is considered as an effective strategy to enhance the Seebeck coefficient, and may consequently boost the thermoelectric performance. Through density-functional theory calculations of Mn-substituted TiFeMnSn compounds, we demonstrate that the d-states of the substituted Mn atoms induce a strong resonant level near the Fermi energy. Our experimental results are in good agreement with the calculations. They show that Mn substitution results in a large increase of the Seebeck coefficient, arising from an enhanced eDOS in Heusler compounds. The results prove that a proper substitution position and element selection can increase the eDOS, leading to a higher Seebeck coefficient and thermoelectric performance of ecofriendly materials.
