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

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).

Effects of Exchange Correlation Functional (Vwdf3) on the Structural, Elastic, and Electronic Properties of Transition Metal Dichalogenides

“…The lattice parameters were calculated such that the three systems can be viewed as having a hexagonal P6_3/mmc symmetry with a lattice constant of 3.66 Å. The Mo-S and S-S bond lengths are 2.415 Å and 3.131 Å respectively which agrees with the available literature [11]. In the case of MoSe2, the bond lengths of Mo-Se and Se-Se atoms were 2.424 Å and 3.113 Å, respectively.…”

“…Table 1 presented the result of the calculated equilibrium lattice parameter of Molybdenum Chalcogenide MoX2 for the three exchange-correlation functional (PBE, rVV10, and vdW-DF3) compared to the available experimental and theoretical results. [18] a(Å) 3.874 3.489 3.551 3.617 3.520 [19] MoTe 2 c(Å) 13.906 13.965 13.817 14.261 13.970 [11] It can be seen that the vdW-DF3 successfully describe accurately the lattice parameter of the three systems with only 1 % error. This shows that the functional performed excellently in the determination of the lattice parameters of a bulk MoX 2 .…”

“…The five elastic constants were used to check the stability of the optimized structure using the Born stability criteria [20] and to determine the Mechanical properties of the materials for the three correlation functional. The calculated properties were compared with the available literature both experimentally and theoretically [21,22,23], which is presented in Table 2. The Born stability criteria were checked using equations ( 2) -(4 [24].…”

Simultaneous quantification of Young’s modulus and dispersion forces with nanoscale spatial resolution

“…H and E then tend to converge to average values which are in relatively good agreement with theoretical expectations and experimental results from the literature (2-30 zJ and 18-24 GPa, respectively). This is an important results because it demonstrates that the method is capable of distinguishing the contributions of local nanoscale features, something usually neglected by existing measurement techniques and models [76][77][78][79][80][81][82][83][84][85][86][87][88]. Previous dynamic and contact mode AFM studies have highlighted the fact that H values tend to be affected by roughness and nanoscale features [89,90].…”

Suspended MoTe2 field effect transistors with ionic liquid gate

“…Upon applying a larger VBG to other suspended devices, the transfer curves were found to differ in repeated gatesweeps and the MoTe2 eventually collapsed to the Si surface. The low Young's modulus of MoTe2, 110 GPa, 26,27 which is about ten times lower than ~1 TPa of carbon nanotubes 28 or graphene, 29 and the relatively long strain relaxation time (~minutes) 30 originating from the structural phase transition between the 1T ` and 2H phases leave the suspended MoTe2 FETs vulnerable to This is the author's peer reviewed, accepted manuscript. However, the online version of record will be different from this version once it has been copyedited and typeset.…”