A single device emulates complex synaptic functions for the first time

A joint research group of International Center for Materials Nanoarchitectonics, NIMS, and Department of Chemistry and Biochemistry, University of California, Los Angeles succeeded in developing a new inorganic device named “synapse device”

National Institute of Materials Science (NIMS) and Japan Science and Technology Agency (JST) announced on June 27, 2011 that a joint research group of International Center for Materials Nanoarchitectonics, NIMS, and Department of Chemistry and Biochemistry, University of California, Los Angeles succeeded in developing a new inorganic device named “synapse device”, which automatically realizes two types of functions analogous to those of the human brain, i.e., memorizing and forgetting. Details are published online in Nature Materials on June 26, 2011*.

The device is made with the atomic switch which consists of an Ag2S-coated metal Ag electrode and a counter electrode of platinum Pt, having a nanometer gap between the two electrodes. The atomic switch works by the formation and annihilation of an Ag-atom bridge between the electrodes, which is realized by controlling the solid-state electrochemical reaction of a mixed ionic and electronic conductor Ag2S.

The research group discovered that the device emulates two types of synaptic function, short-term plasticity and long-term potentiation by varying input pulse repetition time which controls the formation of the Ag-atom bridges.

The published paper in Nature Materials remarks that the Ag2S device indicates a breakthrough in mimicking synaptic behavior essential for further creation of artificial neural systems that emulate human memories.

* Takeo Ohno, Tsuyoshi Hasegawa, Tohru Tsuruoka, Kazuya Terabe, James K. Gimzewski & Masakazu Aono, “Short-term plasticity and long-term potentiation mimicked in single inorganic synapses”, Nature Materials (2011) Published online: 26 June 2011 | doi:10.1038/nmat3054