Chen Yun, Lin Jinguo, Jiang Junjie, Wang Danyang, Yu Yue, Li Shouheng, Pan Jun'an, Chen Haitao, Mao Weiguo, Xing Huanhuan, Ouyang Fangping, Luo Zheng, Zhou Shen, Liu Feng, Wang Shanshan, Zhang Jin
School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, Guangdong, 518055, China.
Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, Hunan Key Laboratory of Mechanism and Technology of Quantum Information, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410000, China.
Adv Mater. 2024 Sep;36(36):e2404734. doi: 10.1002/adma.202404734. Epub 2024 Jul 31.
The van der Waals (vdW) interface provides two important degrees of freedom-twist and slip-to tune interlayer structures and inspire unique physics. However, constructing diversified high-quality slip stackings (i.e., lattice orientations between layers are parallel with only interlayer sliding) is more challenging than twisted stackings due to angstrom-scale structural discrepancies between different slip stackings, sparsity of thermodynamically stable candidates and insufficient mechanism understanding. Here, using transition metal dichalcogenide (TMD) homobilayers as a model system, this work theoretically elucidates that vdW materials with low lattice symmetry and weak interlayer coupling allow the creation of multifarious thermodynamically advantageous slip stackings, and experimentally achieves 13 and 9 slip stackings in 1T″-ReS and 1T″-ReSe bilayers via direct growth, which are systematically revealed by atomic-resolution scanning transmission electron microscopy (STEM), angle-resolved polarization Raman spectroscopy, and second harmonic generation (SHG) measurements. This work also develops modulation strategies to switch the stacking via grain boundaries (GBs) and to expand the slip stacking library from thermodynamic to kinetically favored structures via in situ thermal treatment. Finally, density functional theory (DFT) calculations suggest a prominent dependence of the pressure-induced electronic band structure transition on stacking configurations. These studies unveil a unique vdW epitaxy and offer a viable means for manipulating interlayer atomic registries.
范德华（vdW）界面提供了两个重要的自由度——扭转和滑移，以调节层间结构并激发独特的物理特性。然而，构建多样化的高质量滑移堆叠（即层间晶格取向平行，仅存在层间滑动）比扭转堆叠更具挑战性，这是因为不同滑移堆叠之间存在埃级的结构差异、热力学稳定候选结构稀少以及对其机制的理解不足。在此，本工作以过渡金属二硫属化物（TMD）同质双层为模型系统，从理论上阐明了具有低晶格对称性和弱层间耦合的范德华材料能够产生多种热力学上有利的滑移堆叠，并通过直接生长在1T″-ReS和1T″-ReSe双层中实验实现了13种和9种滑移堆叠，原子分辨率扫描透射电子显微镜（STEM）、角分辨偏振拉曼光谱和二次谐波产生（SHG）测量系统地揭示了这些堆叠。本工作还开发了调制策略，通过晶界（GB）切换堆叠，并通过原位热处理将滑移堆叠库从热力学有利结构扩展到动力学有利结构。最后，密度泛函理论（DFT）计算表明，压力诱导的电子能带结构转变对堆叠构型有显著依赖性。这些研究揭示了一种独特的范德华外延，并为操纵层间原子配准提供了一种可行的方法。
