Valleytronics discovery could help extend limits of Moore’s law

Study finds that light polarization properties of candidate material offer additional computing degrees of freedom.

Valleytronics utilizes different local energy extrema (valleys) with selection rules to store 0s and 1s. In SnS, these extrema have different shapes and responses to different polarizations of light, allowing the 0s and 1s to be directly recognized. This schematic illustrates the variation of electron energy in different states, represented by curved surfaces in space. The two valleys of the curved surface are shown.

A new study by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Shuren Lin of UC Berkeley’s Department of Materials Science and Engineering discovered that valleytronics transistor could one day enable chipmakers to pack more computing power onto microchips.

The continual cramming of more silicon transistors onto chips, known as Moore’s Law. Today, however, chipmakers are concerned that they might soon reach the fundamental limits of conventional materials. Researchers worldwide are concerned and thus hunting for a material’s unique properties to perform more computations in the same space.

Valleytronics, another developing methodology, uses the exceptionally particular reaction of hopeful crystalline materials under particular light conditions to mean their on/off states – that is, utilizing the materials’ band structures with the goal that the data of 1s is put away in discrete vitality valleys of electrons, which are reliant on the precious stone structures of the materials.

During the study, scientists found that the material such as tin(II) sulfide (SnS) can absorb different polarizations of light. The material is also able to re-emit light of different colors at different polarizations. Using it for concurrently accessing both the usual electronic and valleytronic degrees of freedom could generously increment the computing power and data storage density of circuits made with the material.

Lin, the first author of the paper, said the material is different from previously investigated candidate valleytronics materials because it possesses such selectivity at room temperature without additional biases apart from the excitation light source, which alleviates the previously stringent requirements in controlling the valleys. Compared to its predecessor materials, SnS is also much easier to process.

Scientists expect that the finding could help them demonstrate valleytronic devices. The unique coupling between light and valleys in this new material may also pave the way toward future hybrid electronic/photonic chips.

Berkeley Lab’s “Beyond Moore’s Law” initiative use the fundamental science capacities and exceptional client offices of Berkeley Lab and UC Berkeley to assess promising contender for cutting-edge gadgets and processing advancements. Its goal is to fabricate close associations with industry to quicken the time it commonly takes to move from the revelation of an innovation to its scale-up and commercialization.

The study can be read here.