Agradecimentos: The authors would like to thank Dr. Ryan Major and Richard Nay of Hysitron for technical support. The authors thank the Air Force Office of Scientific Research (Grant FA9550-13-1-0084) for funding this research, and Air Force Office of Scientific Research MURI Grant FA9550-12-1-0035...

Agradecimentos: The authors would like to thank Dr. Ryan Major and Richard Nay of Hysitron for technical support. The authors thank the Air Force Office of Scientific Research (Grant FA9550-13-1-0084) for funding this research, and Air Force Office of Scientific Research MURI Grant FA9550-12-1-0035 financial support of this research. YMJ thanks Sao Paulo Research Foundation (FAPESP) Grant No. 2016/12341-5 for financial support. CFW thanks Sao Paulo Research Foundation (FAPESP) Grant No. 2016/12340-9 for financial support. YMJ, CFW and DSG acknowledge the Center for Computational Engineering and Sciences at State University of Campinas (FAPESP/CEPID grant No. 2013/08293-7)

Abstract: Transition metal dichalcogenides are 2D structures with remarkable electronic, chemical, optical and mechanical properties. Monolayer and crystal properties of these structures have been extensively investigated, but a detailed understanding of the properties of their few-layer structures...

Abstract: Transition metal dichalcogenides are 2D structures with remarkable electronic, chemical, optical and mechanical properties. Monolayer and crystal properties of these structures have been extensively investigated, but a detailed understanding of the properties of their few-layer structures are still missing. In this work we investigated the mechanical differences between monolayer and multilayer WSe2 and MoSe2, through fully atomistic molecular dynamics simulations (MD). It was observed that single layer WSe2/MoSe2 deposited on silicon substrates have larger friction coefficients than 2, 3 and 4 layered structures. For all considered cases it is always easier to peel off and/or to fracture MoSe2 structures. These results suggest that the interactions between first layer and substrate are stronger than interlayer interactions themselves. Similar findings have been reported for other nanomaterials and it has been speculated whether this is a universal-like behavior for 2D layered materials. We have also analyzed fracture patterns. Our results show that fracture is chirality dependent with crack propagation preferentially perpendicular to W(Mo)-Se bonds and faster for zig-zag-like defects

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2013/08293-7; 2016/12341-5; 2016/12340-9

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