Phase transition in bilayer MoS₂under tensile loading: a molecular dynamics study.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Molybdenum disulfide (MoS₂) exists in multiple polymorphs with diverse electronic and mechanical properties.
• Strain engineering offers a method to tune MoS₂ morphology and properties.

Purpose of the Study:

• To systematically investigate the phase transition mechanisms of single-layer and bilayer MoS₂ under uniaxial tensile loading.
• To understand the influence of edges and sulfur (S)-line vacancies on these phase transitions.

Main Methods:

• Molecular dynamics simulations were employed to study phase transitions at room temperature.
• Uniaxial tensile conditions were applied to single-layer and bilayer MoS₂.

Main Results:

• Phase transitions initiate near edges and vacancy sites in MoS₂.
• The metastable T″ phase formation precedes the I4/mmm phase, releasing tensile stress.
• Local buckling of the MoS₂ plane occurs with I4/mmm phase growth.
• Tilted S-line vacancies trigger I4/mmm phase initiation to mitigate shear stress.

Conclusions:

• A comprehensive mechanism for MoS₂ phase transitions under tensile loading is elucidated.
• Findings provide guidance for strain engineering MoS₂ in nanoelectronics.