Van der Waals (vdW) structures of two-dimensional materials host a broad range of physical phenomena. New opportunities arise if different functional layers may be remotely modulated or coupled in a device structure. Here we demonstrate the in-situ coherent modulation of moir\'e excitons and correlated Mott insulators in transition metal dichalcogenide (TMD) homo- or hetero-bilayers with on-chip terahertz (THz) waves. Using common dual-gated device structures, each consisting of a TMD moir\'e bilayer sandwiched between two few-layer graphene (fl-Gr) gates with hexagonal boron nitride (h-BN) spacers, we launch coherent phonon wavepackets at ~0.4-1 THz from the fl-Gr gates by femtosecond laser excitation. The waves travel through the h-BN spacer, arrive at the TMD bilayer with precise timing, and coherently modulate the moir\'e excitons or the Mott states. These results demonstrate that the fl-Gr gates, often used for electrical control of the material properties, can serve as effective on-chip opto-elastic transducers to generate THz waves for the coherent control and vibrational entanglement of functional layers in commonly used moir\'e devices.
@article{arxiv.2403.17974,
title = {Coherent Modulation of Two-Dimensional Moir\'e States with On-Chip THz Waves},
author = {Yiliu Li and Eric A. Arsenault and Birui Yang and Xi Wang and Heonjoon Park and Yinjie Guo and Takashi Taniguchi and Kenji Watanabe and Daniel Gamelin and James C. Hone and Cory R. Dean and Sebastian F. Maehrlein and Xiaodong Xu and Xiaoyang Zhu},
journal= {arXiv preprint arXiv:2403.17974},
year = {2024}
}
Comments
11 pages, 4 figures, 12 pages SI. arXiv admin note: substantial text overlap with arXiv:2307.16563