title: Stacking-Dependent Interlayer Coupling in Trilayer MoS₂ with Broken Inversion Symmetry.
abstract: The stacking configuration in few-layer two-dimensional (2D) materials results in different structural symmetries and layer-to-layer interactions, and hence it provides a very useful parameter for tuning their electronic properties. For example, ABA-stacking trilayer graphene remains semimetallic similar to that of monolayer, while ABC-stacking is predicted to be a tunable band gap semiconductor under an external electric field. Such stacking dependence resulting from many-body interactions has recently been the focus of intense research activities. Here we demonstrate that few-layer MoS2 samples grown by chemical vapor deposition with different stacking configurations (AA, AB for bilayer; AAB, ABB, ABA, AAA for trilayer) exhibit distinct coupling phenomena in both photoluminescence and Raman spectra. By means of ultralow-frequency (ULF) Raman spectroscopy, we demonstrate that the evolution of interlayer interaction with various stacking configurations correlates strongly with layer-breathing mode (LBM) vibrations. Our ab initio calculations reveal that the layer-dependent properties arise from both the spin-orbit coupling (SOC) and interlayer coupling in different structural symmetries. Such detailed understanding provides useful guidance for future spintronics fabrication using various stacked few-layer MoS2 blocks.
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
authors.forename: Jiaxu
authors.initials: J
authors.lastname: Yan
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
authors.forename: Juan
authors.initials: J
authors.lastname: Xia
authors.affiliation: NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: Xingli
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , Changchun 130033, P. R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan.
authors.forename: Jer-Lai
authors.initials: JL
authors.lastname: Kuo
authors.affiliation: NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: Beng Kang
authors.initials: BK
authors.lastname: Tay
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: Shoushun
authors.initials: S
authors.lastname: Chen
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
authors.forename: Wu
authors.initials: W
authors.lastname: Zhou
authors.affiliation: NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University , Singapore 639798, Singapore.|School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.|Centre for Disruptive Photonic Technologies, Nanyang Technological University , Singapore 637371, Singapore.
authors.forename: Ze Xiang
authors.initials: ZX
authors.lastname: Shen
keywords: Molybdenum disulfide; first-principles calculations; photoluminescence; stacking; ultralow-frequency Raman spectroscopy