a significant scientific development with profound implications for the future of quantum technologies, researchers at the Indian Institute of Science (IISc), Bangalore, have discovered a novel way to control the behavior of phonons—tiny waves of energy that ripple through the atomic lattice of materials. This finding could pave the way for the creation of highly specialized materials, essential for breakthroughs in thermal management, optics, and electronics at the quantum level. Phonons, though invisible, are powerful. Much like the ripples on the surface of a pond when a stone is dropped, these microscopic waves travel through solid materials when their atoms vibrate. Controlling how these waves behave is crucial for developing advanced devices in areas like photonics and quantum computing, which demand incredibly precise manipulation of energy and information at microscopic scales.
The team at IISc focused their research on a material called tungsten diselenide (WSe₂), a type of two-dimensional crystal. By carefully adjusting the angle at which two ultra-thin layers of this material are stacked—known as the twist angle—they were able to alter how phonons interact. These interactions affect key properties of the material, such as how it responds to heat, light, and electricity.
Using Raman spectroscopy, a powerful technique that reveals how atoms in a material vibrate, the researchers observed remarkable changes when the layers were twisted at angles between 1° and 7°. These small shifts led to a phenomenon called phonon mode splitting, alongside unusual changes in how the material responded to temperature, particularly at extremely low levels (below -223°C). These effects suggest a delicate and complex relationship between electrons and phonons, and how they behave when the structure of a material is subtly altered.
This work, published in the prestigious journal ACS Nano, represents a step forward in our understanding of moiré superstructures—patterns that emerge when two grids overlap slightly out of alignment. These patterns are proving to be fertile ground for discovering new physical phenomena, and this latest study adds valuable insight into how such structures can be tuned for technological use.
Crucially, this research was made possible through the support of the Department of Science and Technology (DST), which funded the Raman spectroscopy facility under its FIST (Fund for Improvement of S&T Infrastructure) program. It’s a shining example of how public investment in science infrastructure can lead to world-class discoveries with real-world applications.
As the global race to develop quantum technologies accelerates, this Indian breakthrough serves as a reminder of the nation’s growing capabilities in cutting-edge research. It offers a glimpse into a future where we can design materials with precision at the atomic level—one twist at a time.
