Yi Cui, Kun Xu, Peiwen Ren, Lin Yuan, Pawel Czaja, Andrew Barnum, Prasanna Sarkar, Aaron Altman, Karen C. Bustillo, S K Kundu, Akash Ramdas, Xueji Wang, Gang Wan, Y. H. Wang, Jiayue Wang, Chengyu Song, Cedric Lim Lim, Qi Zheng, Helen Yao, Tony Heinz, Harold Y. Hwang, Arun Majumdar, Jennifer A. Dionne, Colin Ophus, Felipe H. da Jornada, Robert Sinclair, Yi Cui
Twisted epitaxy enables precise orientation control of nanostructures confined within van der Waals (vdW) gaps. Here, we investigate the moiré and electronic structure of a representative twisted epitaxial system, where Au nanodiscs are grown inside twisted bilayer MoS 2 with a 6° interlayer twist, inducing a 3° symmetrical misalignment of Au relative to each MoS 2 layer (MoS 2 –Au–MoS 2 ). Using multislice electron ptychography (MEP), we resolve the three-dimensional “moiré-of-moirés” structure of MoS 2 –Au–MoS 2 with atomic resolution. Electron energy loss spectroscopy (EELS) shows that MoS 2 encapsulation significantly reduces the plasmon energy of Au nanodiscs compared with their unencapsulated counterparts. Furthermore, first-principles calculations reveal that Au insertion alters the electronic band alignment near the Fermi level of bilayer MoS 2 . Our results introduce a twisted MoS 2 –Au–MoS 2 heterostructure as a structurally and electronically rich material system and establish twisted epitaxy as a new strategy for moiré engineering and the synthesis of 2D-confined materials with tunable optoelectronic properties.