Reviewed by Danielle Ellis, B.Sc.Sep 18 2024
A research team at Chalmers University of Technology in Sweden has made great progress toward developing next-generation nanoelectronics by removing basic noise restrictions. The study was published in Physical Review Letters.
The image illustrates a tiny nanoscale heat engine connecting hot and cold sides. The temperature difference drives a current and generates power, but both current and power are noisy, hindering precise and reliable performance. The Chalmers researchers have managed to demonstrate a trade-off relation between noise and power from these nanoscale engines, paving the way for future nanoscale thermoelectric devices with high precision. Image Credit: Chalmers University of Technology, Carina Schultz
Researchers can create novel material properties that will lead to smaller, faster, and more energy-efficient electronics because of nanoscale devices as small as human cells. But noise needs to be addressed if nanotechnology is to reach its full potential.
Rapid advancements in nanotechnology are generating interest in a variety of sectors, including communications and energy production. At the nanoscale, which is one-millionth of mm, particles obey the laws of quantum mechanics. By utilizing these properties, materials can be engineered to display improved conductivity, magnetism, and energy efficiency.
Today, we witness the tangible impact of nanotechnology – nanoscale devices are ingredients to faster technologies and nanostructures make materials for power production more efficient.
Janine Splettstösser, Professor, Applied Quantum Physics, Chalmers University of Technology
Devices Smaller than the Human Cell Unlocking Novel Electronic and Thermoelectric Properties
Utilizing systems smaller than human cells, known as nanoscale devices, researchers can control charge and energy currents down to the single electron level. These nanoelectronic systems can use quantum mechanical properties to perform specific tasks, acting as "tiny engines."
At the nanoscale, devices can have entirely new and desirable properties. These devices, which are a hundred to ten thousand times smaller than a human cell, allow to design highly efficient energy conversion processes.
Ludovico Tesser, Ph.D. Student, Applied Quantum Physics, Chalmers University of Technology
Navigating Nano-Noise: A Crucial Challenge
However, the advancement of nanotechnology research is severely hampered by noise. This disruptive noise, produced by electrical charge fluctuations and thermal effects within devices, hampered accurate and dependable performance. The mechanisms underlying this noise are not fully understood. Researchers have not been able to determine how much of it can be removed without detrimental energy conversion. Yet now, a Chalmers research team has managed to make a significant advancement in the right direction.
The study examined thermoelectric heat engines at the nanoscale. These specialized tools regulate waste heat and turn it into electrical power.
“All electronics emit heat and recently there has been a lot of effort to understand how, at the nano-level, this heat can be converted to useful energy. Tiny thermoelectric heat engines take advantage of quantum mechanical properties and nonthermal effects and, like tiny power plants, can convert the heat into electrical power rather than letting it go to waste,” said Professor Splettstösser.
Balancing Noise and Power in Nanoscale Heat Engines
However, when exposed to large temperature variations, nanoscale thermoelectric heat engines perform better. These temperature variations make the already difficult noise that researchers are dealing with even more difficult to study and comprehend. The Chalmers researchers, however, have now been able to clarify an important trade-off between power and noise in thermoelectric heat engines.
We can prove that there is a fundamental constraint to the noise directly affecting the performance of the ‘engine’. For example, we cannot only see that if you want the device to produce a lot of power, you need to tolerate higher noise levels, but also the exact amount of noise. It clarifies a trade-off relation, that is how much noise one must endure to extract a specific amount of power from these nanoscale engines. We hope that these findings can serve as a guideline in the area going forward to design nanoscale thermoelectric devices with high precision.
Ludovico Tesser, Ph.D. Student, Applied Quantum Physics, Chalmers University of Technology
The research project is funded by the European Research Council (ERC) under the European Union’s Horizon Europe research and innovation program (101088169/NanoRecycle) and a Wallenberg Academy Fellowship.
Journal Reference:
Tesser, L., & Splettstoesser, J. (2024) Out-of-Equilibrium Fluctuation-Dissipation Bounds. Physical Review Letters. doi.org/10.1103/PhysRevLett.132.186304