Mimicking the brain functions of learning, forgetting and explicit/implicit memories with SrTiO-based memristive devices.

To implement the complex brain functions of learning, forgetting and memory in a single electronic device is very advantageous for realizing artificial intelligence. As a proof of concept, memristive devices with a simple structure of Ni/Nb-SrTiO/Ti were investigated in this work. The functions of learning, forgetting and memory were successfully mimicked using the memristive devices, and the "time-saving" effect of implicit memory was also demonstrated.

Pt/WO3/FTO memristive devices with recoverable pseudo-electroforming for time-delay switches in neuromorphic computing.

A recoverable pseudo-electroforming process was discovered in Pt/WO3/FTO devices. Unlike conventional electroforming, which is usually destructive, pseudo-electroforming can be recovered when the electrical stimulation is removed. Furthermore, the time-dependent recovery process can be tuned by diverse voltage pulses applied in pseudo-electroforming; therefore, the device can be used as a time-delay switch in memristor-based neuromorphic networks.

Revival of "dead" memristive devices: case of WO3-x.

Inappropriate operation could make a memristive device "dead" and cause the loss of resistive switching performance. In this study, the revival of "dead" devices was investigated in the case of WO3-x-based memristive devices. It is believed that inappropriate operation with a high-voltage pulse creates an ordered structure of oxygen vacancies and such an ordered structure makes the normal reset process fail.

Synaptic Metaplasticity Realized in Oxide Memristive Devices.

Metaplasticity, a higher order of synaptic plasticity, as well as a key issue in neuroscience, is realized with artificial synapses based on a WO3 thin film, and the activity-dependent metaplastic responses of the artificial synapses, such as spike-timing-dependent plasticity, are systematically investigated. This work has significant implications in neuromorphic computation.

The role of Schottky barrier in the resistive switching of SrTiO3: direct experimental evidence.

Single crystalline SrTiO3 doped with 0.1 wt% Nb was used as a model system to evaluate the role of the Schottky barrier in the resistive switching of perovskites. The Ti bottom electrode formed an ohmic contact in the Ni/Nb:SrTiO3/Ti stack, whereas the Ni top electrode created a strong Schottky barrier, which was reflected in a huge semi-circle in the impedance spectrum of the stack.