Ionic Pathways to Neuromorphic Function: Direct Visualization of Oxygen Migration in Interface Synaptic Memristive...

Area of Science:

• Materials Science
• Neuroscience
• Electrical Engineering

Background:

• Neuromorphic computing aims to replicate biological synapse efficiency.
• Understanding atomic-scale ionic mechanisms in synaptic devices is crucial but underexplored.
• Oxygen migration in oxide resistive switching devices controls conductance but is difficult to visualize.

Purpose of the Study:

• To investigate the atomic-scale ionic mechanisms in HfO2-based memristors for neuromorphic applications.
• To demonstrate how co-doping and engineered interfaces enhance memristor performance and stability.
• To establish a direct link between ionic motion, defect engineering, and neuromorphic functionality.

Main Methods:

• Fabrication of co-doped HfO2 memristors with engineered oxide-metal interfaces.
• In-operando optical spectroscopies (Raman, photoluminescence, dark-field) for cycle-resolved visualization of ionic dynamics.
• Correlation of electrical performance with spectroscopic signatures.

Main Results:

• Co-doped HfO2 devices function as p-n-like memristors with reversible interfacial ionic motion.
• Engineered interfaces and co-doping stabilize oxygen vacancies and facilitate migration, enabling tunable conductance states.
• Direct visualization confirmed the link between defect engineering, ionic motion, and synaptic plasticity.

Conclusions:

• Co-doping and interface engineering are effective strategies for creating high-performance, stable oxide memristors.
• This work provides the first direct, cycle-resolved evidence of controllable ionic motion driving neuromorphic functionality.
• The findings offer a generalizable approach for designing high-endurance, optically trackable memristive devices.