Entropy-driven docosahedral short-range order in simple liquids and glasses

Area of Science:

• Condensed matter physics
• Materials science
• Statistical mechanics

Background:

• Icosahedral structures are traditionally considered dominant in simple liquids and glasses.
• The precise nature and prevalence of dominant local structures remain unclear.
• Understanding local structures is crucial for explaining phenomena like supercooling and glass transition.

Purpose of the Study:

• To identify the dominant local structure in simple liquids and glasses.
• To investigate the driving forces behind the predominance of specific local structures.
• To elucidate the role of local structures in phase transitions and material properties.

Main Methods:

• Utilized a novel structure descriptor to analyze local atomic arrangements.
• Applied the descriptor to computational models of simple liquids and glasses.
• Examined an experimental colloid glass sample.

Main Results:

• Docosahedral structures were identified as the most favored local arrangement.
• This predominance was observed in both simulated and experimental glass systems.
• The dominance of docosahedral structures was found to be entropy-driven.

Conclusions:

• Docosahedral structures are the predominant local motif in simple liquids and glasses.
• Entropy, rather than enthalpy, drives the prevalence of docosahedral structures.
• These findings provide a significant advancement in understanding supercooling, glass transition, and crystallization.