Engineers at the Massachusetts Institute of Technology have created a "brain on a chip" made up of tens of thousands of artificial synapses called memristors. This is reported in an article published in the journal Nature Nanotechnology. Memristors were made of silicon and an alloy of silver and copper. The created chip is able to memorize visual information and reproduce it more accurately in comparison with existing memristor designs made of undoped components. This will improve neuromorphic devices, which are a kind of electronics that processes information like the human brain.
Such circuits can be embedded in portable devices and perform complex tasks that are currently feasible only for supercomputers. In a neuromorphic device, a memristor acts as a transistor for converting signals, but its principle of operation resembles the work of an interneuronal connection, or synapse. A transistor can transmit information by switching between two values (0 and 1) depending on the strength of the incoming signal (in the form of an electric current), while a memristor is capable of taking on many different states, performing a much wider range of operations.
One memristor consists of an anode and a cathode separated by the medium. When a voltage is applied to one electrode, ions begin to flow through the medium to the other electrode, forming a conduction channel. Existing memristors work well if the voltage provokes a strong flow of electrons. However, in the new microcircuit, the specialists used copper as an alloying element, which stabilizes the flow of ions through the channel. The researchers were able to reproduce the shield images of the Marvel comics character Captain America, with each pixel being associated with a specific memristor in the chip. This allowed the "brain on a crystal" to memorize the picture and reproduce the picture accurately several times.