An international team of scientist from the United States, the United Kingdom and Taiwan has developed the world’s smallest memristor. Their results appear in the journal Nature Nanotechnology.
Hus et al. created the smallest atom-memory unit yet. Image credit: Cockrell School of Engineering, University of Texas at Austin.
In 2018, University of Texas at Austin’s Professor Deji Akinwande and colleagues created what was then the thinnest memory storage device, dubbed ‘atomristor,’ with a single atomic layer of thickness.
In the new work, the researchers reduced the size even further, shrinking the cross section area down to just a single square nanometer.
Getting a handle on the physics that pack dense memory storage capability into these devices enabled the ability to make them much smaller.
Defects, or holes in the material, provide the key to unlocking the high-density memory storage capability.
“When a single additional metal atom goes into that nanoscale hole and fills it, it confers some of its conductivity into the material, and this leads to a change or memory effect,” Professor Akinwande said.
Though the researchers used molybdenum disulfide (MoS2) as the primary nanomaterial in the study, they think the discovery could apply to hundreds of related atomically thin materials.
The race to make smaller chips and components is all about power and convenience. With smaller processors, you can make more compact computers and phones.
But shrinking down chips also decreases their energy demands and increases capacity, which means faster, smarter devices that take less power to operate.
“The results obtained in this work pave the way for developing future generation applications that are of interest to the Department of Defense, such as ultra-dense storage, neuromorphic computing systems, radio-frequency communication systems and more,” said Dr. Pani Varanasi, program manager for the U.S. Army Research Office.
“The scientific holy grail for scaling is going down to a level where a single atom controls the memory function, and this is what we accomplished in the new study,” Professor Akinwande said.
The team’s new device falls under the category of memristors, a popular area of memory research, centered around electrical components with the ability to modify resistance between its two terminals without a need for a third terminal in the middle known as the gate.
That means they can be smaller than today’s memory devices and boast more storage capacity.
This version of the memristor promises capacity of about 25 terabits per square centimeter. That is 100 times higher memory density per layer compared with commercially available flash memory devices.
S.M. Hus et al. Observation of single-defect memristor in an MoS2 atomic sheet. Nat. Nanotechnol, published online November 9, 2020; doi: 10.1038/s41565-020-00789-w