First-Principle Study of the Electronic Structure and Spontaneous Electric Polarization in Double Perovskite Zn2FeTaO6

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.