Nearly Ideal Two-Dimensional Electron Gas Hosted by Multiple Quantized Kronig-Penney States Observed in Few-Layer...

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanoscience

Background:

• Ideal two-dimensional electron gas (2DEG) theoretically features a flat, energy-independent density of states.
• Conventional 2DEG systems in semiconductors and metals have limitations compared to theoretical ideals.
• Few-layer InSe offers a novel platform for exploring 2DEG properties.

Purpose of the Study:

• To achieve and characterize an ideal 2DEG in few-layer indium selenide (InSe) films.
• To investigate the nature of quantized states within these films.
• To provide a theoretical framework explaining the observed 2DEG phenomena.

Main Methods:

• Experimental synthesis of few-layer InSe films.
• Characterization of quantum well states (QWSs) and density of states (DOS).
• Density functional theory (DFT) calculations and Kronig-Penney model simulations.

Main Results:

• Realization of ideal 2DEG with multiple QWSs in few-layer InSe.
• The number of QWSs directly corresponds to the number of atomic layers.
• Observed stair-like DOS and parabolic band dispersions confirming ideal 2DEG characteristics.
• DFT and simulations consistently explain the 2DEG in QWSs.

Conclusions:

• Few-layer InSe films host ideal 2DEG within multiple quantized Kronig-Penney states.
• 2D van der Waals materials are suitable for realizing ideal 2DEG.
• The semiconducting nature of InSe facilitates the development of high-performance electronic devices, such as superlattices with negative differential resistance.