Very low power electronics “straight from the fridge”?
Would a pile of 2D material allow overcurrents at very hot temperatures to be easily obtained in the home kitchen?
An international study published in August opens a new path to high-temperature supercurrents at “hot” temperatures just like inside a kitchen refrigerator.
The ultimate goal is to achieve it superconductivity (i.e., an electric current with no loss of energy from the resistor) at a reasonable temperature.
Towards superconductivity at room temperature
Previously, superconductivity was only possible at very low temperatures, below -170 ° C below zero – Antarctica would also be too hot!
Therefore, the cooling costs of superconductors have been high, as they require expensive and high-energy cooling systems.
Superconductivity at daily temperatures is the ultimate goal of researchers in this field.
This new semiconductor super-grid device could be the basis for a radical new class of ultra-low-power electronics with significantly lower power consumption per computation than ordinary silicon-based (CMOS) electronics.
The goal of the FLEET Center of Excellence is to create such electronics based on new types of conductors that change solid state transistors without resistance at zero and one (i.e., binary switching) at room temperature.
Exciton supercurrents in high energy efficiency electronics
As the charged electrons and holes against the semiconductors are attracted to each other in an attractive way, they can form tightly bound pairs. These composite particles are called excitons, and new atmospheres open up new pathways for temperature-resistant conduction.
Citations can in principle create a quantum state, “superfluid,” which moves together without resistance. With closely related excitons, the surface should be at high temperatures as well as at ambient temperatures.
But unfortunately, because the electron and the hole are next to each other, in practice the excitons have a very short life – just a few nanoseconds, and they don’t have enough time to form a superfluid time.
As a solution, the electron and the hole can be kept separate, separated atomically thin forming layers, creating so-called ‘spatially indirect’ scythons. Electrons and holes move through separate but very close conductive layers. This has a long duration of exciton, and in fact superfluidity has been observed in these systems.
Exciton superfluid, in which countercharged electrons and holes move together in its different layers, leaves so-called ‘supercurrents’ (electrical currents without dissipation) with zero resistance and zero energy dissipated. Thus, it is clear that the future of very low energy electronics is exciting.
Accumulated layers exceed 2D boundaries
Sara Contik, co-author of the study, points out another problem: atomically thin conductive layers are two-dimensional and in 2D systems there are rigid topological quantum constraints found by David Thouless and Michael Kosterlitz (2016 Nobel Prize) at very low temperatures, –170 ° Those that eliminate temperatures above C.
Transition metal dichalcogenide (TMD) is a key difference in the new system with atomically thin accumulated layers of semiconductor materials. three-dimensional.
The topological limits of 2D are overcome using this thin-layer 3D “super-grid”. Alternative layers are doped with excess electrons (n-doped) and excess holes (p-doped) and these form 3D excitones.
The study predicts that excitation supercurrents will be released into the system at hot temperatures of –3 ° C.
David Neilson, who has worked in exciton superfluidity and 2D systems for many years, says, “The proposed super-grid 3D is beyond the topological limits of 2D systems, and supercurrents can be at -3 ° C.” Since electrons and holes are closely linked, further design improvements should bring this to room temperature. ”
“Surprisingly, it is now becoming routine to produce batteries of these thin layers atomically, aligned atomically and keeping them with the weak van der Waals atomic attraction,” explains Professor Neilson. “And while our new research is a theoretical proposition, it is carefully designed to be viable with current technology.”
The study examined superfluidity in a stack of alternating layers of two different single-layer materials (n- and p-doped transition metal dichlogenides WS2 and WSe2).
Reference: “The overuse of three-dimensional electron holes in a superlink near ambient temperature” M. Van der Donck, S. Conti, A. Perali, AR Hamilton, B. Partoens, FM Peeters, and D. Neilson, 25 August 2020. , Physical review B.
DOI 10.1103 / PhysRevB.102.060503
The research was led by FLEET PI Professor David Neilson, working with collaborators from the University of Antwerp (Belgium), Camerino University (Italy) and UNSW Sydney (Australia).
They received support from the Flemish Research Foundation, the Future and Emerging Technologies Flags of the European Research Area Program and the Australian Research Council (Center of Excellence program).