| 密度泛函理论模拟外电场对铁氧体电子结构的影响 |
| Effect of external electric field on the electronic structure of ferrite using the density functional theory simulation |
| 作者 | 单位 | E-mail | | 黄寒梅 | 四川文理学院化学化工学院, 纤维材料复合技术达州市重点实验室, 达州 635000 | | | 魏世勇 | 湖北民族大学化学与环境工程学院, 恩施 610000 | | | 陈晓龙 | 四川文理学院化学化工学院, 纤维材料复合技术达州市重点实验室, 达州 635000 | | | 谢中奎 | 四川文理学院化学化工学院, 纤维材料复合技术达州市重点实验室, 达州 635000 | | | 向文军 | 四川文理学院化学化工学院, 纤维材料复合技术达州市重点实验室, 达州 635000 | | | 王锐 | 四川文理学院化学化工学院, 纤维材料复合技术达州市重点实验室, 达州 635000 | wangrui20190819@163.com |
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| 摘要: 通过密度泛函理论(DFT)模拟了3种典型的铁氧体(Fe2O3、Fe3O4和α-FeOOH)受外电场作用下的电子结构，研究了外电场对不同铁氧体电子结构的影响。DFT模拟结果显示：外电场的存在能够有效提高Fe2O3、Fe3O4和α-FeOOH晶体结构的价带位置，从而导致3种铁氧体的带隙出现明显的降低；当外电场强度为0.01 V·nm-1时，Fe2O3、Fe3O4和α-FeOOH的带隙分别降低了0.36、0.12和0.34 eV；当电场增大至0.1 V·nm-1时，Fe2O3晶体出现击穿现象，Fe—O化学键断裂导致Fe原子的电子沿外电场方向高度离域至相邻Fe原子，而Fe3O4和α-FeOOH则仅出现不同价带能级电子局域性增强且能量同质化，因而显示出相对稳定的物理化学结构。此外，外电场的存在可导致3种铁氧体价带电子均出现简并现象，且随电场强度增大而增强。3种铁氧体中，外电场的存在导致Fe2O3晶体中Fe原子的电荷密度增大而降低O原子的电荷密度； Fe3O4晶体结构中不同配位结构的Fe原子以及配位O原子的Hirshfeld电荷几乎不受外电场的影响； α-FeOOH晶体中共边FeO6配位结构的Hirshfeld电荷受外电场影响较小，而共角FeO6配位结构的Hirshfeld电荷受外电场影响较大，且H原子的电荷在强外电场作用下发生歧化响应。随着外电场强度逐渐增大，Fe3O4晶体的电子自旋态密度逐渐增大，而α-FeOOH晶体的电子自旋态密度则显示出降低的规律。 |
| 关键词: 外电场 铁氧体 电子结构 密度泛函理论模拟 |
| 基金项目: 国家自然科学基金地区项目(No.42067007)、四川文理学院高层次人才引进项目(No.2022GCC07Z)、纤维材料复合技术达州市重点实验室开放基金项目(No.XWCL202201)和四川文理学院大学生科研项目(No.X2022Z027)资助。 |
| Abstract: In this work, the electronic structure of three ferrites, Fe2O3 (hematite), Fe3O4 (magnetite), and α-FeOOH (goethite), have been calculated with the density functional theory (DFT) under external electric field (E) for investigating the effect of the external electric field on the electronic structure of ferrites. It was found that the external electric field could continue to decrease the band gap by 0.36, 0.12, and 0.34 eV under an E of 0.01 V·nm-1 through signally changing the valance band maximum. When it increased to 0.1 V·nm-1, Fe2O3 would be broken down by the external electronic field, causing a breaking of the Fe—O bond and a delocalization among Fe atoms along the E direction. At the same time, Fe3O4 and α-FeOOH could maintain their crystal with some effect on the localization and energy of the electron. In addition, it showed a degeneration of the valance electron for three ferrites under the external electric field. For Fe2O3, the Hirshfeld charge of the Fe atoms was reduced while improved for the O atoms along with an increase in the external electronic field. Interestingly, the Hirshfeld charge for both Fe atoms with the form charge of +2 and +3 in Fe3O4 was not influenced by the external electronic field. As for α-FeOOH, the unit of FeO6 located on the edge of the chain was more sensitive than that of the body FeO6 in the chain towards the external electronic field. Meanwhile, the H atom of the terminated -OH in α-FeOOH exhibited a disproportionated response on the Hirshfeld charge under the external electronic field. With the spin of electrons in ferrites, increasing the external electronic field would improve the spin of electrons in Fe3O4 while reducing it in α-FeOOH among an E of 0.001-0.1 V·nm-1. |
| Keywords: external electric field ferrite electronic structure density functional theory simulation |
| 投稿时间：2023-06-14 修订日期：2023-12-22 |
| 摘要点击次数: 1232 |
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| 黄寒梅,魏世勇,陈晓龙,谢中奎,向文军,王锐.密度泛函理论模拟外电场对铁氧体电子结构的影响[J].无机化学学报,2024,40(2):361-372. |
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