基于第一性原理方法,我们研究了双钙钛矿Zn2FeTaO6的晶体结构、电子结构、以及铁电性质。计算结果表明Zn2FeTaO6中的Zn2+离子,Fe3+离子和Ta5+离子均偏离氧八面体的中心。同时,基于线性响应理论Born有效电荷计算显示其自发电极化强度为79.6 μC/cm2。我们还利用杂化泛函理论进一步研究了Zn2FeTaO6的能带结构,发现带隙宽度约为2.6 eV,与多铁材料BiFeO3接近,显示Zn2FeTaO6在铁电光伏领域的潜在应用。 Based on density-functional theory, we have studied the crystal structure, electronic structure, and ferroelectric properties of double perovskite Zn2FeTaO6. It was revealed that Zn2+, Fe3+, and Ta5+ ions in Zn2FeTaO6 displaced away from the center of their oxygen octahedrons. With born effective charge from linear response theory, a large spontaneous electric polarization of 79.6 μC/cm2 was found. Further calculations based hybrid functional show a band gap of around 2.6 eV, which is similar to BiFeO3 and shows its potential application in ferroelectric photovoltaics.
第一性原理,Zn2FeTaO6,多铁性,铁电光伏, First Principles Zn2FeTaO6 Multiferroics Ferroelectric Photovoltaics双钙钛矿Zn2FeTaO6电子结构和自发电极化的第一性原理研究
Li M. R.实验测量结果发现Zn2FeTaO6的晶体结构具有R3c对称性,这是一种极性结构。在本文的计算中,我们利用实验测量的晶体结构作为计算初始结构,并不断进行结构优化,直到找到能量最低的稳定晶体结构为止。由于B位Fe3+离子是磁性金属离子,在计算中我们还进一步考虑Zn2FeTaO6中B位Fe3+离子间的不同磁性耦合方式。我们的计算结果表明,Zn2FeTaO6中的Fe3+离子间更加倾向于反铁磁交换作用,与B位Fe3+离子间铁磁耦合的构型相比,反铁磁耦合时总能量的值约低49.39 meV/f.u.。由于B位的由Fe3+和Ta5+两种元素交替占据,相对于LiNbO3结构,体系的对称性进一步降低。
刘仕晨,蔡田怡,雎 胜. 双钙钛矿Zn2FeTaO6电子结构和自发电极化的第一性原理研究 First-Principle Study of the Electronic Structure and Spontaneous Electric Polarization in Double Perovskite Zn2FeTaO6[J]. 应用物理, 2016, 06(03): 23-29. http://dx.doi.org/10.12677/APP.2016.63004
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