Atomic-Scale Visualization of Polar Domain Boundaries in Ferroelectric In₂Se₃ at the Monolayer Limit

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanoscience

Background:

• Domain boundaries in ferroelectric materials possess unique properties relevant to nanoelectronics and quantum information technology.
• The intricate atomic and electronic structure of these domain boundaries is not fully understood, hindering technological advancements.

Purpose of the Study:

• To directly visualize the atomic structure of polar domain boundaries in two-dimensional (2D) ferroelectric β'-In2Se3.
• To investigate these structures down to the monolayer limit.
• To elucidate the relationship between atomic structure and electronic properties of domain boundaries.

Main Methods:

• Utilized scanning tunneling microscopy and spectroscopy (STM/S) for atomic-scale imaging and electronic characterization.
• Employed density functional theory (DFT) calculations to complement experimental observations and interpret structural details.

Main Results:

• Successfully visualized the atomic structure of polar domain boundaries in monolayer β'-In2Se3.
• Observed a distinct double-barrier energy potential across the 60° tail-to-tail domain boundaries.
• Determined the width of this potential barrier to be approximately 3 nm.

Conclusions:

• The study provides unprecedented atomic-level insight into domain boundary structures in 2D ferroelectrics.
• The findings deepen the fundamental understanding of ferroelectric domain boundaries.
• This research is expected to drive innovation in the application of 2D ferroelectric materials for advanced electronic devices.