论文标题
抗抗毒性硫代基因甲晶晶石BAZRS3薄膜中的铁电偏振
Ferroelectric Polarization in Antiferroelectric Chalcogenide Perovskite BaZrS3 Thin Film
论文作者
论文摘要
块状硫酸硫酸果皮钙钛矿BAZRS3（BZS）在可见区域具有直接带隙，是一种重要的光伏材料，尽管由于其抗fiferroeledelectric（AF）性质，但适用性有限。目前，由于反转对称中心的丧失，基于铁维岩的光伏（FE）光伏引起了人们对环境稳定性和更好的能量转换效率的极大关注。我们使用温度依赖性的拉曼研究和第一原则计算，报告了BZS薄膜的抗纤维自由 - 弗洛电（AF-FE）阶段。 Fe阶段的起源是由A7G〜300 cm-1和B1G5〜420 cm-1模式的异常行为确定的，涉及在Zrs6 oct oct的顶端位点原子的振动。此外，出现低于60 K，B1G1和B2G2（〜85 cm-1）模式，而B12G（〜60 cm-1）消失了，以通过局部失真来稳定针对铁电的PNMA结构。在这里，B2G2和B1G2涉及以AF方式的BA原子的振动，而B1G1也涉及Octahedra的旋转。我们的第一原理计算证实，由于存在氧气（O）杂质，因此Fe是ZRS6八面体中反转对称中心对称性丧失的结果。
Bulk chalcogenide perovskite BaZrS3 (BZS), with a direct band gap in visible region, is an important photovoltaic material, albeit with limited applicability owing to its antiferroelectric (AF) nature. Presently, ferroelectric (FE) perovskite-based photovoltaics are attracting enormous attention for environmental stability and better energy conversion efficiency through enhanced charge separation, owing to loss of center of inversion symmetry. We report on antiferroelectric-ferroelectric (AF-FE) phases of BZS thin film, grown with chemical vapor deposition (CVD), using temperature-dependent Raman investigations and first-principles calculations. The origin of FE phases is established from anomalous behavior of A7g ~ 300 cm-1 and B1g5 ~ 420 cm-1 modes, which involves the vibration of atoms at apical site of ZrS6 octahedra. Additionally, below 60 K, B1g1 and B2g2 ( ~ 85 cm-1) modes appear whereas B12g (~ 60 cm-1) disappears to stabilize the Pnma structure against ferroelectricity by local distortion. Here, B2g2 and B1g2 involve vibrations of Ba atoms in AF manner while B1g1 involves, in addition, the rotation of octahedra as well. Our first-principles calculations confirm that FE appears as a result of loss of center of inversion symmetry in ZrS6 octahedra due to existence of oxygen (O) impurities placed locally at apical sites of sulfur (S) atom.
