Non-volatile optical switch of resistance in photoferroelectric tunnel junctions

In the quest for energy efficient and fast memory elements, optically controlled ferroelectric memories are promising candidates. Here, we show that, by taking advantage of the imprint electric field existing in the nanometric BaTiO3 films and their photovoltaic response at visible light, the polarization of suitably written domains can be reversed under illumination. We exploit this effect to trigger and measure the associate change of resistance in tunnel devices. We show that engineering the device structure by inserting an auxiliary dielectric layer, the electroresistance increases by a factor near 2x10(3)%, and a robust electric and optic cycling of the device can be obtained mimicking the operation of a memory device under dual control of light and electric fields. Designing energy efficient and fast optoelectric neuromorphic systems remains a challenge. Long et al. report that the combined optical-electric stimulus enables switching the ferroelectric polarization and cycling the resistance state of BaTiO3 tunnel barriers, showing that the optical control of resistance is non-volatile.

Automated summary

Optically controlled ferroelectric memories show promise for energy efficient and fast memory elements. By exploiting the imprint electric field and photovoltaic response in nanometric BaTiO3 films, it is possible to reverse polarization under illumination, trigger resistance changes in tunnel devices, and achieve robust cycling of resistance through dual control of light and electric fields. Designing energy efficient and fast optoelectric neuromorphic systems remains a challenge.