Understanding and controlling phase transitions are fundamental to physics and central to many technological revolutions. There is currently strong interest in materials with coupled structural and electronic phase transitions, where controlling the transition plasticity naturally yields built-in memory—a key step in emulating neurons and synapses for “neuromorphic” or brain-like computing technologies.

A team of UC San Diego researchers led by physics professor Oleg Shpyrko developed a new approach to coherent X-ray diffraction—a microscopy technique that is highly sensitive to specific nanoscale domain configurations —that allowed them to observe dynamics within a neuristor (a man-made device that mimics the brain’s neurons) made of vanadium dioxide while electricity was applied.

By taking measurements while operating the neuristor, they discovered a strategy to make the material learn and forget a specific state, opening an avenue toward developing energy-efficient brain-inspired hardware.