Abstract

The accumulation and extrusion of Ca2+ in the pre- and postsynaptic compartments play a critical role in initiating plastic changes in biological synapses. To emulate this fundamental process in electronic devices, we developed diffusive Ag-in-oxide memristors with a temporal response during and after stimulation similar to that of the synaptic Ca2+ dynamics. In situ high-resolution transmission electron microscopy and nanoparticle dynamics simulations both demonstrate that Ag atoms disperse under electrical bias and regroup spontaneously under zero bias because of interfacial energy minimization, closely resembling synaptic influx and extrusion of Ca2+, respectively. The diffusive memristor and its dynamics enable a direct emulation of both short- and long-term plasticity of biological synapses, representing an advance in hardware implementation of neuromorphic functionalities.

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Acknowledgements

This work was supported in part by the US Air Force Research Laboratory (AFRL) (Grant No. FA8750-15-2-0044), the Intelligence Advanced Research Projects Activity (IARPA) (contract 2014-14080800008), US Air Force Office for Scientific Research (AFOSR) (Grant No. FA9550-12-1-0038), and the National Science Foundation (NSF) (ECCS-1253073). Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of AFRL. Part of the device fabrication was conducted in the clean room of the Center for Hierarchical Manufacturing (CHM), an NSF Nanoscale Science and Engineering Center (NSEC) located at the University of Massachusetts Amherst. The TEM work used resources of the Center for Functional Nanomaterials, which is a US DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704. The authors thank M. McLean for useful discussions on computing.

Author information

Author notes

    • Zhongrui Wang
    •  & Saumil Joshi

    These authors contributed equally to this work.

Affiliations

  1. Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA

    • Zhongrui Wang
    • , Saumil Joshi
    • , Hao Jiang
    • , Rivu Midya
    • , Peng Lin
    • , Qiangfei Xia
    •  & J. Joshua Yang
  2. Department of Physics, Loughborough University, Loughborough LE11 3TU, UK

    • Sergey E. Savel’ev
  3. Hewlett Packard Labs, Palo Alto, California 94304, USA

    • Miao Hu
    • , Ning Ge
    • , John Paul Strachan
    • , Zhiyong Li
    •  & R. Stanley Williams
  4. Air Force Research Lab, Information Directorate, Rome, New York 13441, USA

    • Qing Wu
    •  & Mark Barnell
  5. Biology Department, University of Massachusetts, Amherst, Massachusetts 01003, USA

    • Geng-Lin Li
  6. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA

    • Huolin L. Xin

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Contributions

J.J.Y. conceived the concept. J.J.Y., Q.X., Z.W. and S.J. designed the experiments. Z.W. fabricated the devices and S.J. performed electrical measurements. S.E.S. performed the simulation. H.L.X. carried out the in situ TEM characterizations. H.J., R.M., P.L., M.H., N.G., J.P.S., Z.L., Q.W., M.B., G.-L.L. and R.S.W. helped with experiments and data analysis. J.J.Y., Q.X., Z.W., S.J., S.E.S. and R.S.W. wrote the paper. All authors discussed the results and implications and commented on the manuscript at all stages.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Zhongrui Wang or Saumil Joshi or J. Joshua Yang.

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DOI

https://doi.org/10.1038/nmat4756

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