Physicists create device for imitating biological memory

On-chip brain. Credit: Elena Khavina/MIPT Researchers from the Moscow Institute of Physics and Technology have created a device that acts like a synapse in the living brain, storing information and gradually forgetting it when not accessed for a long time. Known as a second-order memristor, the new device is based on hafnium oxide and offers prospects for designing analog neurocomputers imitating the way a biological brain learns. The findings are reported in ACS Applied Materials & Interfaces . Neurocomputers, which enable artificial intelligence, emulate brain function. Brains store data in the form of synapses, a network of connections between neurons. Most neurocomputers have a conventional digital architecture and use mathematical models to invoke virtual neurons and synapses. Alternatively, an actual on-chip electronic component could stand for each neuron and synapse in the network. This so-called analog approach has the potential to speed up computations drastically and reduce energy costs. The core component of a hypothetical analog neurocomputer is the memristor . The word is a portmanteau of "memory" and "resistor," which pretty much sums up what it is: a memory cell acting as a resistor. Loosely speaking, high resistance encodes a zero, and low resistance encodes a one. This is analogous to how a synapse conducts a signal between two neurons (one), while the absence of a synapse results in no signal, a zero. But there is a catch: In an actual brain, the active synapses tend to strengthen over time, while the opposite is true for inactive ones. This phenomenon, known as synaptic plasticity, is one of the foundations of natural learning and memory. It explains the biology of cramming for an exam and why our seldom-accessed memories fade. Proposed in 2015, the second-order memristor is an attempt to reproduce natural memory, complete with synaptic plasticity. The first […]

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