Wang Su-Yun, Li De-Kang, Zha Ming-Jie, Yan Xiao-Qing, Liu Zhibo, Tian Jianguo
The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and Teda Applied Physics Institute, Nankai University, Tianjin 300071, China.
Renewable Energy Conversion and Storage Center, Nankai University, Tianjin 300071, China.
ACS Nano. 2023 Aug 22;17(16):16230-16238. doi: 10.1021/acsnano.3c06031. Epub 2023 Aug 2.
Twisted van der Waals structures exhibit a variety of unusual electrical and optical phenomena and could provide a powerful means for designing nanodevices with tunable chiral properties. However, programming intrinsic chiral properties of the film on the atomic scale remains a great challenge due to the limitations of fabrication and measurement techniques. Here, we report a highly tunable large optical activity of twisted anisotropic two-dimensional (2D) materials, including black phosphorus (BP), ReS, PdSe, and α-MoO, by varying the twist angle between the stacked layers. The chirality can be deliberately tailored through the engineering of the symmetry, band structure, and anisotropy of 2D materials, demonstrating the high tunability of the chirality. The results show the highest thickness-normalized ellipticity value (13.8 deg μm, twisted ReS) and ellipticity value (1581 mdeg, twisted BP) among the systems based on 2D materials. It is also shown that the chiroptical response exists in an extremely large spectral range from the visible to the infrared. Furthermore, the twisted ReS enabled spin-selective control of the information transformation. These results show that highly controllable chirality in twisted 2D anisotropic materials has considerable potential in on-chip polarization optics, nano-optoelectronics, and biology.
扭曲的范德华结构展现出各种不同寻常的电学和光学现象，并且可为设计具有可调手性特性的纳米器件提供一种强大的手段。然而，由于制造和测量技术的限制，在原子尺度上对薄膜的本征手性特性进行编程仍然是一个巨大的挑战。在此，我们报道了通过改变堆叠层之间的扭曲角，扭曲的各向异性二维（2D）材料（包括黑磷（BP）、ReS、PdSe和α-MoO）具有高度可调的大光学活性。通过对二维材料的对称性、能带结构和各向异性进行调控，可以有意地定制手性，这证明了手性的高度可调性。结果表明，在基于二维材料的体系中，扭曲的ReS具有最高的厚度归一化椭圆率值（13.8度·微米）和椭圆率值（1581毫度，扭曲的BP）。研究还表明，旋光响应存在于从可见光到红外光的极宽光谱范围内。此外，扭曲的ReS实现了对信息转换的自旋选择性控制。这些结果表明，扭曲的二维各向异性材料中高度可控的手性在片上偏振光学、纳米光电子学和生物学方面具有相当大的潜力。
