Coexistence of short- and long-term memory in NbO_x-based memristor for a nonlinear reservoir computing system

Abstract

In this study, TiN/NbO_x/Pt memristor devices with short-term memory (STM) and self-rectifying characteristics are used for reservoir computing. The STM characteristics of the device are detected using direct current sweep and pulse transients. The self-rectifying characteristics of the device can be explained by the work function differences between the TiN and Pt electrodes. Furthermore, neural network simulations were conducted for pattern recognition accuracy when the conductance was used as the synaptic weight. The emulation of synaptic memory and forgetfulness by short-term memory effects are demonstrated using paired-pulse facilitation and excitatory postsynaptic potential. The efficient training reservoir computing consisted of all 16 states (4-bit) in the memristor device as a physical reservoir and the artificial neural network simulation as a read-out layer and yielded a pattern recognition accuracy of 92.34% for the modified National Institute of Standards and Technology dataset. Finally, it is found that STM and long-term memory in the device coexist by adjusting the intensity of pulse stimulation.

Graphical abstract

Keywords

memristor / resistive switching / neural network / reservoir computing

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Declarations

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Author contributions

Heesung Jang: Formal analysis; Investigation – performed the experiments; Resources; Writing – original draft. Jungang Heo, Jihee Park, Hyesung Na: Investigation – data/evidence collection; Computation; Formal analysis. Sungjun Kim: Conceptualization; Writing – review & editing; Resources; Project administration; Funding acquisition.

Data availability

The data that support the findings of this study are available within the article and its supplementary material and from the corresponding authors upon reasonable request.

Electronic supplementary materials

The online version contains supplementary material available at https://doi.org/10.15302/frontphys.2025.014208.

Acknowledgements

This work was supported in part by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT (RS-2024-00356939 and RS-2024-00405691).

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