Building the atom-cluster models, the electronic structure and chemical bonds of Ca3Co2O6 and Ca-for-Sr substitution were calculated by density function and discrete variation method(DFT-DVM). The semiconductor properties of these two systems were shown from the gap between the highest valence band( HVB) and the lowest con-duction(LCB). Furthermore, the gap of Sr-doped one was less than that of Ca3Co2O6. The HVB and LCB were mainly contributed from Co3d and ()2p atomic orbitals, which indicated obviously that ID Co-O chains play an important role in electric property of Ca3Co206 and doped system. It can be concluded that chemical bonds of Co-O chains in Sr-doped are weaker than those of Ca3C02O6 from comparing covalent bond orders and atomic net charges. Thus thermoelectric properties may be improved from Ca-for-Sr substitution in Ca3Co2O6.%通过建立原子簇模型,运用密度泛函离散变分法讨论了Ca3 C02 O6及掺Sr体系的电子结构与化学键.掺Sr前后价带和导带之间的能隙宽度表现出半导体特征,且掺Sr后能隙变窄,价带和导带主要由Co3d和O2p轨道贡献,表明一维Co-O链在电学性能方面起主导作用.通过对化学键分析可知,掺Sr后有利于降低Co-O链的键性.由此可知,掺Sr有利于改善Ca3Co2O的热电性能.
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