Programmable Ferroelectricity in Hf_0.5Zr_0.5O₂ Enabled by Oxygen Defect Engineering

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Ferroelectricity in hafnia-based materials is crucial for Si-compatible electronics.
• Distinguishing intrinsic ferroelectric polarization from polar phases and oxygen vacancies is a significant challenge.

Purpose of the Study:

• To demonstrate electrically controllable ferroelectricity in a Hf_0.5Zr_0.5O₂ heterostructure.
• To utilize a mixed ionic-electronic conductor electrode for manipulating ferroelectric properties.
• To achieve multilevel polarization states for advanced electronic applications.

Main Methods:

• Fabrication of a Hf_0.5Zr_0.5O₂ heterostructure with Sr-doped LaMnO₃ electrode.
• In situ macroscopic characterization and atomic imaging of oxygen vacancy dynamics.
• Electrical modulation of ferroelectric polarization states.

Main Results:

• Achieved electrically reversible oxygen vacancy extraction and insertion in Hf_0.5Zr_0.5O₂.
• Demonstrated multilevel polarization states controlled by electric fields.
• Confirmed the role of the mixed conductor in enabling advanced ferroelectric functionality.

Conclusions:

• The mixed ionic-electronic conductor electrode facilitates the control and utilization of ferroelectric properties.
• Programmed ferroelectric heterostructures with Si-compatible doped hafnia are promising for future electronic devices.
• This work offers a pathway for developing next-generation ferroelectric memory and logic applications.