摘要
采用基于密度泛函理论（DFT）的全势线性缀加平面波（FPLAPW）方法，对Sn掺杂钙钛矿BaTiO3电子结构进行了第一性原理研究，构造了3个不同的超胞，分别为1×2×2、1×1×3和1×1×2，即：分别由4个、3个和2个单胞组成的超胞。研究表明：当X≤0．33时，随着X值的增大，相应的费米面会向Sn掺杂BaTiO3导带的更高的能量处移动，以适应掺杂电子数目的增多，其态密度的演化可以用一个严格的带状模型来描述，所以，掺入BaTiO3体系的每一个电子都对体系的导电过程有贡献，从而使其室温介电常数大幅度提高，介电损失相对减小。复合材料的态密度的重新分布主要是由O—P与所掺入的Sn混合后的杂化而引起的。
Electronic structures of Sn-doped perovskite BaTiO3 have been investigated within the first-principles full potential linearized augmented plane-wave （FP-LAPW） method using three different supercell1×2×2、1×1×3 and 1×1×2, and containing two, three and four basic units respectively. Results reveal that, with increasing x （x=0, 0.25, 1/3. in other words, x≤〈0.33）, the band of Ba （SnxTi1-x）O3 system shifts up to higher energies above the Fermi level to accommodate the increased number of doped electrons, and it can be described fairly well within a rigid-band model, this shows that every electron doped into the system contributes to the conduction process, so it can highly increase the dielectric constant at room temperature and decrease the dielectric losing. It is clear that these redistributions within the primarily oxygen p band arises from hybridization mixing with such Sn-derived states.
