On the Elastic Properties and Fracture Patterns of MoX2 (X = S, Se, Te) Membranes: A Reactive Molecular Dynamics Study

Marcelo Lopes Pereira Júnior,Rafael Timóteo De Sousa Júnior,José Moreira De Sousa,Cícera Maria Viana De Araújo,William Ferreira Giozza,Luiz Fernando Roncaratti Júnior,Luiz Antonio Ribeiro Júnior

doi:10.3390/condmat5040073

Marcelo Lopes Pereira Júnior, Rafael Timóteo De Sousa Júnior + Show 5 more

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https://doi.org/10.3390/condmat5040073

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Abstract

We carried out fully-atomistic reactive molecular dynamics simulations to study the elastic properties and fracture patterns of transition metal dichalcogenide (TMD) MoX2 (X = S, Se, Te) membranes, in their 2H and 1T phases, within the framework of the Stillinger–Weber potential. Results showed that the fracture mechanism of these membranes occurs through a fast crack propagation followed by their abrupt rupture into moieties. As a general trend, the translated arrangement of the chalcogen atoms in the 1T phase contributes to diminishing their structural stability when contrasted with the 2H one. Among the TMDs studied here, 2H-MoSe2 has a higher tensile strength (25.98 GPa).

Highlights

Transition metal dichalcogenide (TMD) monolayers are atomically thin semiconductors that belong to the family of 2D nanosheets [1,2]
This rupture trend is different from the one obtained for the 2H-MoS2 case, in which two well concise MoS2 fragments were produced as a final stage of the fracture process. This brittle signature for the 1T-MoS2 case is obtained for 5.60% of strain. These results suggest that the translated arrangement of the chalcogen atoms in the 1T phase is crucial in diminishing the structural stability of TMDs
We carried out fully-atomistic reactive molecular dynamics simulations to perform a comparative study on the elastic properties and fracture patterns of MoX2 (X = S, Se, Te) membranes, in the 2H and 1T phases, within the framework of the Stillinger–Weber potential

Summary

Introduction

Transition metal dichalcogenide (TMD) monolayers are atomically thin semiconductors that belong to the family of 2D nanosheets [1,2]. By using density functional theory and reactive molecular dynamic simulations, theoretical studies have predicted Young’s modulus values for single-layer MoS2, MoSe2, and MoTe2 ranging in the intervals 170–250 GPa [21,25,34], 165–185 GPa [39,46], and 60–115 GPa [42,44,45], respectively. These works promoted substantial advances in understanding the mechanical properties of TMDs. an overall description of their elastic properties and fracture dynamics is still missing. A detailed description of the mechanical properties of these nanostructures considering both 2H and 1T phases is highly attractive

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