Scientists at Rice University have jumped over an important barrier for emerging phonon-based technologies. They reached this groundbreaking advance by investigating a phenomenon of strong quantum interference known as Fano resonance. Shengxi Huang, an associate professor of electrical and computer engineering and materials science and nanoengineering, leads the team. The researchers have shared their findings in the journal Science Advances. You can read the full study at DOI 10.1126/sciadv.adw1800. It shows that the recently observed Fano resonance is two orders of magnitude larger than any previously reported.
The study shines a light on the special characteristics of phonons, quantized modes of vibrations that happen in all materials. Phonons tend to fall by the wayside to flashier, more photonic-charged particles like electrons and photons. This study proves there’s gold in their hills — for all sorts of uses. Kunyan Zhang, a former postdoctoral researcher at Rice, was the lead on this study. He is likewise first author of the study.
Unraveling Fano Resonance
Fano resonance captures a more general interference effect often received in condensed matter physics, consisting of interference between two phonons with distinct frequency distributions. To accomplish these incredible findings, the researchers used a two-dimensional metal intercalated between a layer of graphene and silicon carbide. This targeted approach provided the team with an opportunity to track interference at levels never before seen. It uncovered the influence of various silicon carbide surface terminations on Raman line shapes.
Kunyan Zhang noted the significance of their findings: “While this phenomenon is well-studied for particles like electrons and photons, interference between phonons has been much less explored.” He noted that this lack of oversight constitutes a great loss, because phonons are able to keep their wave-like characteristics for much longer intervals. This structural stability is critical to achieving high performance devices.
The research team creatively employed a two-dimensional metal to enhance interference. This discovery greatly improves the coupling between distinct vibrational modes in silicon carbide. Zhang explained, “The 2D metal triggers and strengthens the interference between different vibrational modes in silicon carbide, reaching record levels.”
Implications for Sensing and Beyond
What’s particularly impressive about this newly discovered interference is the sensitivity. Zhang highlighted that “this interference is so sensitive that it can detect the presence of a single molecule.” This ability to discriminate between molecular structures makes phonon-based technologies strong contenders for advanced molecular sensing applications.
We did comparative studies on three kinds of silicon carbide surface termination. Those results showed an unambiguous relationship between each surface and its characteristic Raman line shape. These incredible measurements confirmed the team’s findings. In doing so, they lay a promising groundwork for future investigations that will advance molecular sensing methods.
Shengxi Huang elaborated on the broader implications of their work, stating, “This phonon-based approach not only advances molecular sensing but also opens up exciting possibilities in energy harvesting, thermal management, and quantum technologies, where controlling vibrations is key.” Due to their versatility phonon-based technologies are likely to be an integral part of all major industrial applications going forward.
Future Prospects for Phonon-Based Technologies
The preliminary study carried out at Rice University opens the door to exciting new research into the implications of phonon interference and advances the groundwork for future applications. As Huang noted, “Compared to conventional sensors, our method offers high sensitivity without the need for special chemical labels or complicated device setup.” This simplicity would manifest in more affordable, easier-to-use, and identical sensing technologies into the natural sciences, engineering, and architecture disciplines.
It has placed researchers in an exciting position to begin exploring what their findings mean in practice. Theoretical understanding of Fano resonance is a major scientific breakthrough that significantly broadens the academic frontier. It creates tremendous possibilities for breakthroughs that can revolutionize fields that rely on accurate measurement and manipulation of molecular interactions.