Smart objects are required to store and retrieve massive amounts of data quickly without consuming too much power. Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved functionality in a material called molybdenum ditelluride. The two-dimensional material stacks into multiple layers to build a memory cell.
Chipmakers have long needed better memory technologies to enable a growing network of smart devices. One of these next-generation possibilities is resistive random access memory (RRAM).
In RRAM, an electrical current is typically driven through a memory cell made up of stacked materials, creating a change in resistance that records data as 0s and 1s in memory. The sequence of 0s and 1s among memory cells identifies pieces of information that a computer reads to perform a function and then store into memory again.
A material would need to be robust enough for storing and retrieving data at least trillions of times, but materials currently used have been too unreliable; therefore, RRAM hasn't been available yet for widescale use on computer chips. Molybdenum ditelluride could potentially last through all those cycles. The material allows a system to switch more quickly between 0 and 1, potentially increasing the rate of storing and retrieving information. This is because when an electric field is applied to the cell, atoms are displaced by a tiny distance, resulting in a state of high resistance, noted as 0, or a state of low resistance, noted as 1, that can occur much faster than switching in conventional RRAM devices.
Because less power is needed for these resistive states to change, a battery could last longer. In a computer chip, each memory cell would be located at the intersection of wires, forming a memory array called cross-point RRAM.
Future work involves building a stacked memory cell that also incorporates the other main components of a computer chip: logic, which processes data, and interconnects, which are wires that transfer electrical signals.