Temperature-dependent failure of atomically thin MoTe₂.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Molybdenum ditelluride (MoTe2) is a 2D material with potential applications in electronics and mechanics.
• Understanding its mechanical properties, especially under tensile stress and varying temperatures, is crucial for its practical use.
• This study focuses on the trigonal prismatic phase (2H-MoTe2).

Purpose of the Study:

• To investigate the mechanical responses and tensile behavior of 2H-MoTe2 using molecular dynamics (MD) simulations.
• To examine crack formation and propagation under uniaxial tensile stress in armchair and zigzag directions at different temperatures.
• To assess the impact of temperature on Young's modulus and fracture stress-strain relationships.

Main Methods:

• Molecular dynamics (MD) simulations employing Stillinger-Weber (SW) potentials.
• Simulations conducted at temperatures ranging from 10 K to 600 K at 100 K intervals.
• Analysis of crack formation and propagation using Ovito visualizer at various strain rates (10^-4 ps^-1).

Main Results:

• Fracture strength of 2H-MoTe2 at 10 K is 16.33 GPa (armchair) and 13.71 GPa (zigzag).
• At 600 K, fracture strength decreases to 10.81 GPa (armchair) and 10.13 GPa (zigzag).
• Temperature significantly affects fracture strain and mechanical strength in both armchair and zigzag orientations.

Conclusions:

• The mechanical strength and fracture behavior of 2H-MoTe2 are highly sensitive to temperature.
• Tensile stress in the armchair direction generally results in higher fracture strength compared to the zigzag direction.
• MD simulations provide valuable insights into the temperature-dependent mechanical properties of 2D MoTe2.