论文标题
在二维层间滑动铁电极中的可切换和不可交呼的散装光伏效应
Switchable and unswitchable bulk photovoltaic effect in two-dimensional interlayer-sliding ferroelectrics
论文作者
论文摘要
自发极化和大量光伏效应（BPVE）是铁电材料中的两个伴随物理特性。铁电顺序的翻转通常伴随着BPVE的切换，因为它们两个都在反转对称性下逆转。在这项研究中，我们报告了具有二维（2D）层间滑动铁电材料中具有独特的BPVE特征，这些材料具有不可交换的平面内BPVE（XY平面中的光诱导的光电流）和可切换的平面外BPVE（沿Z区沿Z-Direction的光诱导极化）。抽象双层晶体模型和第一原理计算中的对称分析验证了这些BPVE特性。这是因为由层间滑动引起的正和负铁电状态与无法翻转所有bpve张量元件的镜像相关。这一发现扩展了对铁电性与BPVE之间关系的理解。一方面，可切换的平面外BPVE可用于设计可切换的光电设备。另一方面，平面内BPVE对铁电的翻转非常健壮，并且不可交呼的特征有益于构建大型光电设备。
Spontaneous polarization and bulk photovoltaic effect (BPVE) are two concomitant physical properties in ferroelectric materials. The flipping of ferroelectric order usually accompanies with the switching of BPVE as both of them are reversed under the inversion symmetry. In this study, we report the distinctive BPVE characters in two-dimensional (2D) interlayer sliding ferroelectric materials featuring unswitchable in-plane BPVE (light-induced photocurrent in the xy plane) and switchable out-of-plane BPVE (light-induced polarization along the z-direction). Symmetry analysis within abstract bilayer crystal model and first-principles calculations validate these BPVE properties. It is because the positive and negative ferroelectric states caused by interlayer sliding are related by mirror symmetry which cannot flip all the BPVE tensor elements. This finding extends the understanding of the relationship between ferroelectricity and BPVE. On one hand, the switchable out-of-plane BPVE can be used to design switchable photoelectric devices. On the other hand, the in-plane BPVE is robust against the ferroelectric flipping, and the unswitchable character is beneficial to construct larger-scale photoelectric devices.
