Professor Isao H. Inoue


National Institute of Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan

Artificial neuron and synapse based on SrTiO3.

This talk aims to advocate a right way to mimic a biological neural system by a proper electronic circuit, i.e., to utilise an attractor formation of nonlinear dynamical systems for an edge device which autonomously studies inputs and decides outputs without connecting to any external cloud computers. Then, I discuss the essential aptitudes of electronic devices such as artificial synapse and neuron to be used in such attractor circuits.  As an example, we show our artificial neuron which exhibits leaky-integrate functionality without the help of any external capacitors and resistors. Because the capacitor for an analogue circuit which tries to mimic the leaky-integration is huge in size, the property of our artificial neuron without capacitor is a significant advantage for the device integration (for miniaturisation). This artificial neuron of ours is made of a single SrTiO3 field effect transistor (FET).  Furthermore, the same single SrTiO3 FET can also become the spike-timing-dependent plasticity (STDP) synapse. The artificial synapse based on SrTiO3 exhibits a much larger dynamic range and much lower energy consumption compared to the recent emerging artificial synapses such as those utilising resistance switchings (RRAMs and memristors).  Just for a curiosity (not relevant), both our artificial STDP synapse and artificial LIF neuron are compared with the biological counterparts as shown in Fig. 1. Especially for the neuron, the coincidence in time-scale and output-ratio are almost perfect.  A virtual back-gate due to the oxygen vacancy migration and piling up, as well as the formation of two dimensional  electron gas in the SrTiO3 FET would be essential key ingredients to understand why our SrTiO3 FET behaves as the artificial neuron and synapse; this issue is further discussed in the talk. Short Biography Dr Isao H. Inoue received BSc, MSc, and DSc degrees in Physics from the University of Tokyo in 1990, 1992 and 1998, respectively. He became a researcher with tenure of the Electrotechnical Laboratory (ETL) in 1992 and a senior researcher in 1999. From 1999 to 2001, he was a visiting scholar at Cavendish Laboratory, University of Cambridge. In 2001, ETL was reorganised to AIST; since then, he has been a senior researcher of the National Institute of Advanced Industrial Science and Technology (AIST). He has been investigating on a wide range of research field: from the strongly correlated oxides to the neuromorphic electronic devices. isaocaius@gmail.com; https://sites.google.com/view/isao/

Date: Mon 18 Mar 2019

Start Time: 14:30

End Time: 15:30

1061 | Electrical Eng. Building