Microscopic structural origin of slow dynamics in glass-forming liquids

Area of Science:

• Condensed matter physics
• Materials science
• Chemical physics

Background:

• Supercooled liquids exhibit slow dynamics, with the underlying mechanisms linked to structural properties but not fully understood.
• The fragility of glass-forming liquids, describing deviations from simple Arrhenius-like behavior, is a key characteristic of their dynamics.

Purpose of the Study:

• To investigate the relationship between structure and dynamics in model glass-forming liquids.
• To elucidate the role of the T1 process in determining liquid fragility and dynamic behavior.

Main Methods:

• Numerical simulations of model glass-forming liquids.
• Analysis of the elementary particle rearrangement mode known as the T1 process.
• Correlation of T1 process characteristics with structural order preservation and cooperativity.

Main Results:

• The ability of a T1 process to preserve local glassy structural order dictates liquid fragility.
• T1 processes that disrupt order occur independently, leading to Arrhenius-like dynamics.
• T1 processes that maintain order propagate cooperatively, resulting in super-Arrhenius-like dynamics.

Conclusions:

• A microscopic link between structural ordering, dynamic cooperativity, and super-Arrhenius-like dynamics in supercooled liquids has been established.
• The T1 process serves as a critical determinant of liquid fragility and dynamic behavior.
• This work advances the understanding of structure-dynamics relationships in supercooled liquids.