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arXiv 0704.2985cond-mat.mtrl-scicond-mat.str-el
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BaFeO3电子结构的从头算DFT研究

Electronic structure of BaFeO3: an abinitio DFT study

Hong-Jian Feng, Fa-Min Liu

摘要:

采用密度泛函理论(DFT)方法对BaFeO 3(BFO)的基态电子性质进行了第一性原理计算研究.采用广义梯度近似(GGA)交换关联泛函和Vosko-Wilk-Nusair关联能泛函插值方法,系统地研究了不同晶面的能带结构、态密度和电子分布。计算结果表明,多数自旋能带结构的带隙为2.7012 eV,少数自旋能带结构的带隙为0.6867 eV。上旋Fe t2 g被完全占据,下旋Fe eg是空的。此外,上自旋Fe eg和下自旋Fe t2 g在费米能级附近被部分占据,导致有限态密度。Fe ~(4+)-O-Fe ~(4+)平面超交换耦合使磁性有序重新排列,使铁磁特性成为可能,而沿c轴的四重位移则使钙钛矿材料获得铁电特性。这些原因可能导致这样的事实,即四元相BFO可能是一个潜在的多铁性,而它是在非常实验条件下产生的。沿不同晶面的电荷密度表明,O和Fe之间的强共价键可以用来研究交换耦合,这种强杂化可能会进一步增加超交换耦合,以增强磁有序。

英文摘要:

First principles calculations were performed to study the ground state electronic properties of BaFeO3 (BFO) within the density functional theory (DFT). Adopting generalized gradient approximation (GGA) exchange and correlation functional and Vosko-Wilk-Nusair correlation energy functional interpolation, we have systematically conducted the band structure, density of states and electronic distribution along different crystalline planes. Calculating results show that band gap in the majority spin band structure and band gap in the minority spin band structure were found to be 2.7012 eV and 0.6867 eV respectively. Up-spin Fe t2g were fully occupied and down-spin Fe eg were empty. Moreover, the up-spin Fe eg and down-spin Fe t2g were partially occupied near the Fermi energy, leading to a finite density of states. The Fe4+-O-Fe4+ plane superexchange coupling should rearrange the magnetic order to make the ferromagnetic characteristic being possible, moreover the tetragonal displacement along the c axis could induce the perovskites materials to acquire ferroelectric property. These reasons could lead to the fact that the tetragonal phase BFO could be a potential multiferroics while it was produced under the very experimental conditions. The charge density along different crystalline planes were illustrated to show that strong covalent bonding between O and Fe can be used to investigate the exchange coupling, and this strong hybridization may further increase the superexchange coupling to enhance the magnetic ordering.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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