Quantum mechanical rippling of a MoS2 monolayer controlled by interlayer bilayer coupling.
Nanoscale corrugations are of great importance in determining the physical properties of two-dimensional crystals. However, the mechanical behavior of atomically thin films under strain is not fully understood. In this Letter, we show a layer-dependent mechanical response of molybdenum disulfide (MoS(2)) subject to atomistic-precision strain induced by 2H-bilayer island epitaxy. Dimensional crossover in the mechanical properties is evidenced by the formation of star-shaped nanoripple arrays in the first monolayer, while rippling instability is completely suppressed in the bilayer. Microscopic-level quantum mechanical simulations reveal that the nanoscale rippling is realized by the twisting of neighboring Mo-S bonds without modifying the chemical bond length, and thus invalidates the classical continuum mechanics. The formation of nanoripple arrays significantly changes the electronic and nanotribological properties of monolayer MoS(2). Our results suggest that quantum mechanical behavior is not unique for sp(2) bonding but general for atomic membranes under strain.
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 and Graphene Research Center, 6 Science Drive 2, National University of Singapore, Singapore 117546.
Yi
Y
Zheng
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
Jianyi
J
Chen
Institute of High Performance Computing, Agency for Science, Technology and Research, 1 Fusionopolis Way, No. 16-16 Helios, Singapore 138632.
M-F
MF
Ng
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
Hai
H
Xu
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
Yan Peng
YP
Liu
Bruker Singapore, 11 Biopolis Way, No. 10-10 Helios, Singapore 138667.
Ang
A
Li
Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 3 Research Link, Singapore 117602.
Sean J
SJ
O'Shea
Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455,USA.
T
T
Dumitrică
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 and Graphene Research Center, 6 Science Drive 2, National University of Singapore, Singapore 117546.
Kian Ping
KP
Loh