Twisted epitaxy of gold nanodiscs grown between twisted substrate layers of molybdenum disulfide

We expand the concept of epitaxy to a regime of “twisted epitaxy” with the epilayer crystal orientation between two substrates influenced by their relative orientation. We annealed nanometer-thick gold (Au) nanoparticles between two substrates of exfoliated hexagonal molybdenum disulfide (MoS2) with varying orientation of their basal planes with a mutual twist angle from 0° to 60°. Transmission electron microscopy studies show that the Au alignment is midway between that of the top and bottom MoS2 when the twist angle of the bilayer is small (< ~7°). For larger twist angles, Au has only a small misorientation with the bottom MoS2 that varies approximately sinusoidally with the twist angle of the bilayer MoS2. Four-dimensional scanning transmission electron microscopy analysis further reveals a periodic strain variation (< |±0.5%|) in the Au nanodiscs associated with the twisted epitaxy, consistent with the Moiré registry of the two MoS2 twisted layers.