Dimension effect on ferroelectricity: a first-principles study on GeS nanoribbons.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Low-dimensional ferroelectricity is crucial for miniaturized electronic devices.
• Understanding the impact of dimensionality on ferroelectric properties is essential.
• Group-IV monochalcogenides offer promising avenues for exploring ferroelectricity.

Purpose of the Study:

• To investigate the dimension effect on the ferroelectricity of group-IV monochalcogenide MX nanoribbons.
• To analyze how termination and ribbon structure influence ferroelectric polarization.
• To determine critical widths for phase transitions in these nanoribbons.

Main Methods:

• Utilized first-principles calculations to model and analyze nanoribbon structures.
• Examined H-terminated and bare armchair and zigzag group-IV monochalcogenide nanoribbons.
• Calculated in-plane and out-of-plane polarization, and identified phase transition points.

Main Results:

• H-terminated armchair nanoribbons show large in-plane polarization, converging with 2D materials as width increases.
• Out-of-plane polarization in H-terminated armchair nanoribbons appears only for odd ribbon widths (n).
• Bare armchair nanoribbons transition to a paraelectric phase below a critical width of n=10.
• H-terminated zigzag nanoribbons exhibit polarization in both out-of-plane and width directions.
• Bare zigzag nanoribbons are predicted to be polar ferromagnetic metals.

Conclusions:

• The ferroelectricity of group-IV monochalcogenide nanoribbons is highly sensitive to dimensionality, termination, and structural configuration.
• Specific terminations and ribbon types (armchair vs. zigzag) lead to distinct polarization behaviors and potential applications.
• These findings provide insights for designing novel low-dimensional ferroelectric materials for advanced electronic devices.