Heterobilayer Ferroelectricity with Competitive Polarization

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Chemistry

Background:

• Two-dimensional (2D) ferroelectrics are crucial for next-generation low-power electronic devices.
• Experimental realization of 2D ferroelectrics with large out-of-plane polarization (OOP) is challenging due to material limitations.

Purpose of the Study:

• To identify novel 2D semiconducting heterobilayer ferroelectrics with enhanced out-of-plane polarization.
• To discover materials with low energy barriers for sliding ferroelectric switching.
• To develop a predictive physical model for heterobilayer ferroelectric behavior.

Main Methods:

• High-throughput computational screening of 24,960 heterobilayer configurations.
• Analysis of polarization, sliding barriers, and electronic properties.
• Development of a multiscale physical model combining structural projection and polarization decomposition.

Main Results:

• Identified 43 semiconducting heterobilayer ferroelectrics with OOP exceeding MoS₂/WS₂ and low sliding barriers (<100 meV/f.u.).
• CdO/InN demonstrated an OOP ~50 times greater than MoS₂/WS₂ with a low sliding barrier of ~35 meV/f.u.
• Established a link between monolayer properties and heterobilayer ferroelectric response, revealing dipole competition.

Conclusions:

• A significant library of 2D ferroelectric heterobilayers with promising properties for electronic applications has been generated.
• CdO/InN emerges as a top candidate for high-performance, low-power ferroelectric devices.
• The developed physical model provides fundamental insights into the mechanisms governing sliding ferroelectricity in heterobilayers.