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Updated: Dec 17, 2025

Fabricating van der Waals Heterostructures with Precise Rotational Alignment
Published on: July 5, 2019
Phonon Polaritons in Twisted Double-Layers of Hyperbolic van der Waals Crystals
Zebo Zheng1, Fengsheng Sun1, Wuchao Huang1
1State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China.
Abstract:
Controlling the twist angle between two stacked van der Waals (vdW) crystals is a powerful approach for tuning their electronic and photonic properties. Hyperbolic media have recently attracted much attention due to their ability to tailor electromagnetic waves at the subwavelength-scale which, however, usually requires complex patterning procedures. Here, we demonstrate a lithography-free approach for manipulating the hyperbolicity by harnessing the twist-dependent coupling of phonon polaritons in double-layers of vdW α-MoO3, a naturally biaxial hyperbolic crystal. The polariton isofrequency contours can be modified due to this interlayer coupling, allowing for controlling the polaritonic characteristics by adjusting the orientation angles between the two layers. Our findings provide opportunities for control of nanoscale light flow with twisted stacks of vdW crystals.
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