Li Zeya, Huang Junwei, Zhou Ling, Xu Zian, Qin Feng, Chen Peng, Sun Xiaojun, Liu Gan, Sui Chengqi, Qiu Caiyu, Lu Yangfan, Gou Huiyang, Xi Xiaoxiang, Ideue Toshiya, Tang Peizhe, Iwasa Yoshihiro, Yuan Hongtao
National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
College of Engineering and Applied Sciences, and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing, 210023, China.
Nat Commun. 2023 Sep 9;14(1):5568. doi: 10.1038/s41467-023-41295-6.
Van der Waals dielectrics are fundamental materials for condensed matter physics and advanced electronic applications. Most dielectrics host isotropic structures in crystalline or amorphous forms, and only a few studies have considered the role of anisotropic crystal symmetry in dielectrics as a delicate way to tune electronic properties of channel materials. Here, we demonstrate a layered anisotropic dielectric, SiP, with non-symmorphic twofold-rotational C symmetry as a gate medium which can break the original threefold-rotational C symmetry of MoS to achieve unexpected linearly-polarized photoluminescence and anisotropic second harmonic generation at SiP/MoS interfaces. In contrast to the isotropic behavior of pristine MoS, a large conductance anisotropy with an anisotropy index up to 1000 can be achieved and modulated in SiP-gated MoS transistors. Theoretical calculations reveal that the anisotropic moiré potential at such interfaces is responsible for the giant anisotropic conductance and optical response. Our results provide a strategy for generating exotic functionalities at dielectric/semiconductor interfaces via symmetry engineering.
范德华电介质是凝聚态物理和先进电子应用的基础材料。大多数电介质具有晶体或非晶形式的各向同性结构，只有少数研究将各向异性晶体对称性在电介质中的作用视为调节沟道材料电子特性的一种微妙方式。在此，我们展示了一种层状各向异性电介质SiP，其具有非简单对称的二重旋转C对称性，作为一种栅极介质，它可以打破MoS原有的三重旋转C对称性，从而在SiP/MoS界面实现意想不到的线性偏振光致发光和各向异性二次谐波产生。与原始MoS的各向同性行为不同，在SiP栅控MoS晶体管中可实现并调制高达1000的各向异性指数的大电导各向异性。理论计算表明，此类界面处的各向异性莫尔势是造成巨大各向异性电导和光学响应的原因。我们的结果提供了一种通过对称性工程在电介质/半导体界面产生奇异功能的策略。
