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Updated: May 12, 2025
06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
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Phase transitions and dimensional cross-over in layered confined solids
Yong Wang1,2, Junjie Wang1, Ge Yao1
1School of Physics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
Summary
Confined atomic systems exhibit unique solid phases and melting behaviors. Multilayer systems transition through a hexatic phase before melting, unlike 2D layers, due to evolving topological defects.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Understanding solid phases and phase transitions in confined systems is crucial for materials design.
- The behavior of matter under confinement, particularly at the nanoscale, often deviates from bulk properties.
- Order-disorder transitions in two-dimensional (2D) versus three-dimensional (3D) systems present distinct challenges.
Purpose of the Study:
- To investigate the nature of solid phases and melting transitions in noble gases and aluminum confined between graphene sheets.
- To explore the crossover from 2D to 3D behavior in multilayer confined systems.
- To elucidate the role of topological defects in the melting process of confined solids.
Main Methods:
- Utilized crystal structure search methods to identify novel confined solid structures.
- Employed molecular dynamics simulations powered by machine-learned potentials with quantum-mechanical accuracy.
- Analyzed phase transitions under varying pressures and temperatures for different numbers of confined layers.
Main Results:
- Identified non-close-packed structures in multilayer confined solids.
- Observed that 2D monolayers melt via the Kosterlitz-Thouless-Halperin-Nelson-Young theory.
- Discovered a continuous transition to an intermediate hexatic phase in multilayer systems before discontinuous melting into a liquid.
- This hexatic phase was observed up to 12 layers.
Conclusions:
- The melting behavior of confined multilayer systems differs significantly from 2D monolayers.
- An intermediate hexatic phase emerges in multilayer systems due to the crossover from 2D to 3D topological defects during melting.
- These findings offer insights into the fundamental physics of phase transitions in low-dimensional and confined materials.
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