Structural Design of 2D Materials for Future Computing

The unique layered structures of 2D materials offer possibilities to design new atomic structures with rich physics and novel functions. In this talk, I will present our work on the well-controlled structural design of 2D materials and heterostructures, including on-chip phase engineering based on Pd-PdSe2 material system, and van der Waals (vdW) heterostructures (“atomic lego”) based on mechanical stacking of 2D materials, and show the corresponding device functionalities by design. First, I will introduce our work of in situ synthesizing 2D materials through on-device phase engineering [1]. Second, I will present our capability of accurate control of the twist angle in graphene moiré heterostructures. Such capability facilitates the observation of tunable quantum criticalities in an experimental simulator of the extended Hubbard model with spin–valley isospins arising in chiral-stacked twisted double bilayer graphene [2]. The results demonstrate a highly tunable solid-state simulator with intricate interplay of multiple degrees of freedom for exploring exotic quantum critical states and behaviors. Moreover, by fabricating double-aligned magic angle twisted bilayer graphene, we observed the coexistent ferroelectricity and Chern insulating states, and demonstrate the noise-immune neuromorphic computing technology based on the selective and quasi-continuous ferroelectric switching in such ferroelectric Chern insulators [3]. Finally, I will present our work based on vdW vertical heterostructures comprised of transition metal transition metal dichalcogenides, which can be exploited to realize neuromorphic computing devices, such as highly robust memristors based on graphene/MoS_2–xO_x/graphene vdW heterostructure [4]. Our experimental results on a prototype reconfigurable neural network vision sensor based on a WSe₂/BN heterostructure [5], and in-sensor broadband convolutional processing using a band-alignment-tunable PdSe₂/MoTe₂ heterostructure [6] will also be presented.

[1]Xiaowei Liu, et. al, Nature Materials (2024)
[2]Qiao Li, et. al., Nature 609, 479 (2022).
[3]Moyu Chen, et al., Nature Nanotechnology (2024, in press)
[4] Miao Wang, et. al., Nature Electronics 1, 130 (2018).
[5] Chen-Yu Wang, et. al., Science Advances 6, eaba6173 (2020).
[6] Lejing Pi, et al., Nature Electronics 5, 248 (2022).