Low-Field-Driven Domain Wall Motion in Wurtzite Ferroelectrics.

Area of Science:

• Materials Science
• Solid-State Physics
• Nanoscience

Background:

• Wurtzite-type nitride ferroelectrics offer promise for silicon-compatible nonvolatile memory.
• Existing polarization reversal mechanisms lead to high coercive fields and wake-up effects, hindering device reliability.

Purpose of the Study:

• To resolve challenges in wurtzite ferroelectric device operation by enabling low-field-driven domain wall motion.
• To investigate and manipulate the polarization switching dynamics in representative wurtzite ferroelectrics.

Main Methods:

• In situ transmission electron microscopy (TEM) to observe domain wall motion.
• First-principles simulations to quantify energy barriers for different domain wall propagation modes.
• Controlled nucleation polarity to influence domain wall dynamics.

Main Results:

• Polarization switching observed to occur via transverse domain wall propagation, preceding longitudinal motion.
• A 98% reduction in energy barrier for transverse domain wall migration compared to longitudinal motion was quantified.
• Coercive fields reduced by 25%, with high remanent polarization maintained and wake-up effects eliminated across large-area films.

Conclusions:

• The study demonstrates a novel, low-field switching mechanism in wurtzite ferroelectrics driven by transverse domain wall motion.
• This approach fundamentally challenges the conventional Kolmogorov-Avrami-Ishibashi model for ferroelectric switching kinetics.
• The findings establish a universal design principle for developing stable, low-energy ferroelectric devices for large-scale CMOS integration.