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Updated: May 18, 2026
06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Unveiling Layer-Dependent Phase Transition and Lattice Dynamics in Two-Dimensional InSe
Wenqian Shen1,2,3, Lok Wing Wong4, Huizhong Bai1,4
1Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, China.
Advanced Materials (Deerfield Beach, Fla.)
|May 16, 2026
Summary
Discover how the thickness of two-dimensional indium selenide (2D InSe) influences its phase transitions under pressure. Thinner InSe flakes require more energy for phase transitions due to quantum confinement and defect effects.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Two-dimensional (2D) indium selenide (InSe) exhibits unique properties like superior ballistic transport and thermoelectric effects.
- These properties stem from its van der Waals (vdW) layered structure, influencing interlayer and intralayer interactions.
- Vibrational modes in 2D InSe are sensitive to sample thickness, impacting phase transition behaviors.
Purpose of the Study:
- To investigate the effect of thickness on the vibrational behavior of 2D InSe during pressure-induced phase transitions.
- To construct a pressure-layer number (LN) phase diagram for β-InSe.
- To understand the underlying mechanisms, including quantum confinement and defect effects, governing these transitions.
Main Methods:
- Raman spectroscopy was employed to analyze β-InSe flakes with varying layer numbers (4 to 33) under high pressure.
- Photoluminescence (PL) experiments were conducted to corroborate findings.
- Density Functional Theory (DFT) calculations were performed to support experimental observations.
Main Results:
- A pressure-layer number (LN) phase diagram for β-InSe was successfully constructed.
- Thinner InSe flakes (fewer layers) unexpectedly require higher energy to undergo phase transitions.
- Quantum confinement and defect effects were identified as key factors influencing the transition energy, independent of pressure direction.
Conclusions:
- The study reveals a thickness-dependent phase transition behavior in 2D InSe under pressure.
- Quantum confinement and defect effects play a crucial role in modulating phase transitions in few-layer InSe.
- This research provides a foundation for engineering lattice dynamics in vdW materials via pressure manipulation.
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