Researchers at ETH Zurich have built a perovskite-based memristor just 5 nanometres thick. The component has three stable resistive states, and as a result, it can not only store the 0 or 1 of a standard bit, but can also be used for information encoded by three states – the 0, 1 and 2 of a “trit”. This component could, therefore, be useful for a new type of IT that is not based on binary logic, but on a logic that provides for information located ‘between’ the 0 and 1, with interesting implications for what is referred to as fuzzy logic, which seeks to incorporate a form of uncertainty into the processing of digital information.

Another potential application is neuromorphic computing, which aims to use electronic components to reproduce the way in which neurons in the brain process information. The scientists explain that the properties of a memristor at a given point in time depend on what has happened before, and this mimics the behavior of neurons, which only transmit information once a specific activation threshold has been reached.

The researchers have characterized the ways in which the component works by conducting electro-chemical studies. They were able to identify the carriers of electrical charge and understand their relationship with the three stable states, which is important knowledge for materials science which will be useful in refining the way the storage operates and in improving its efficiency.

Memristors (or RRAM memory cells) are much sought-after electronic components that could one day replace flash memory (DRAM) used in USB memory sticks, SD cards and SSD hard drives. They require less energy since they work at lower voltages and can be made much smaller than today’s memory modules. They therefore offer much greater density, which means that they can store more megabytes of information per square millimetre. Memristors are currently, however, only at the prototype stage.