Domain-Wall Tunneling Electroresistance Effect.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Ferroelectric tunnel junctions (FTJs) offer novel functionalities due to ferroelectric domain walls (DWs).
• Previous studies reported metastable and irreversible in-plane head-to-head DW states in FTJs.
• Reversible control of DW states is crucial for practical applications.

Purpose of the Study:

• To demonstrate a stable and reversible head-to-head DW state in FTJs.
• To explore the impact of interface engineering on DW stability and reversibility.
• To predict the emergence of a tunneling electroresistance effect based on DW states.

Main Methods:

• Density functional theory (DFT) calculations were employed to investigate DW stability.
• Phenomenological modeling was used to analyze polarization states and hysteresis loops.
• Quantum transport calculations predicted the tunneling electroresistance effect.

Main Results:

• Stable and reversible head-to-head DW states were achieved by engineering La_{1-x}Sr_{x}O/TiO_{2} interfaces.
• A critical stoichiometry (x≤0.4) was identified for the DW state to become a global minimum.
• Calculated hysteresis loops showed three reversible polarization states, indicating robust control.

Conclusions:

• Interface engineering is key to realizing stable and reversible DW states in FTJs.
• The identified FTJ structures exhibit tunable polarization and promise for novel electronic devices.
• A reversible tunneling electroresistance effect is predicted, driven by the conductive DW state.