Nanotechnology

Quasiparticle research provides new insights into tellurene, paving the way for next-generation electronics

Calculated phonon polarity and band structure of few-layer tellurium and bulk tellurium. (A) Calculated A1 phonon frequency. (B) Calculated change in dipole moment due to A1 mode as a function of thickness. (C-F) Top and side views on the experimental geometry showing the calculated lattice vibrations of the A1 mode in 2L tellurium and bulk tellurium. Red arrows represent atomic vibrations. (G) Calculated bandgap of tellurene as a function of thickness. Calculated band structures of (H) 2L tellurium and (I) bulk tellurium. Credit: Science Advances (2025). DOI: 10.1126/sciadv.ads4763

To explain how matter works on infinitesimal scales, researchers use a single concept to describe collective behavior, such as when a group of birds flying in synchrony is called a “flock” or “buzz.” Specify. The phenomena known as quasiparticles to which these concepts refer could be the key to next-generation technologies.

In a recent study published in Science Advances, a research team led by Shengxi Huang, assistant professor of electrical and computer engineering, materials science, and nanoengineering at Rice University, found that one such type of quasiparticle, a polaron, was the first explains how it works in the nanomaterial tellurene. The material, synthesized in 2017, is made up of small chains of tellurium atoms and has properties useful for sensing, electronic, optical, and energy devices.

“Tellurene exhibits dramatic changes in its electronic and optical properties when its thickness is reduced to a few nanometers compared to its bulk state,” said Rice Ph.D. alumnus, lead author of the study. said Kunian Chan. “Specifically, these changes change how electricity flows and how the material vibrates. We traced it back to changes in polarons as tellurene becomes thinner.”

Polarons are formed when charge-carrying particles, such as electrons, interact with vibrations within the atomic or molecular lattice of a material. Imagine a phone ringing in a packed auditorium during a lecture. Just as the audience shifts their gaze en masse to the source of the interruption, the lattice vibrations also adjust their orientation according to the charge carriers and organize around an aura of polarization. Name of quasiparticle.

Depending on how thin the tellurine layer is, the magnitude of this reaction, and thus the range of the aura, can vary significantly. Understanding this polaron transition is important because it reveals how the fundamental interactions between electrons and vibrations influence the behavior of materials, especially in low dimensions.

“This knowledge could inform the design of advanced technologies, such as more efficient electronic devices and new sensors, and help us understand the physics of materials at the smallest scales,” the paper said. said author Huang.

The researchers hypothesized that as tellurene moves from bulk to nanometer thickness, polarons change from large, spread-out electronic vibrational interactions to smaller, localized interactions. Computational and experimental measurements confirmed this scenario.

“We analyzed how vibrational frequencies and linewidths vary with thickness and correlated these with changes in electrical transport properties, complemented by structural distortions observed with X-ray absorption spectroscopy.” said Zhang. “Furthermore, we developed a field theory that accounts for the effects of enhanced electronic and vibrational coupling in thinner layers.”

The team’s comprehensive approach provided deeper insight than previously into the dynamics of polarons that depend on tellurene thickness. This has been possible thanks to both the improved advanced research techniques introduced and the recent development of high-quality tellurene samples.

“Our findings reveal how polarons affect electrical transport and optical properties as tellurene becomes thinner,” Zhang said. “In thinner layers, polarons localize charge carriers, leading to reduced charge carrier mobility. This phenomenon is particularly important in modern devices that are continually miniaturized and rely on thinner materials for functionality. is extremely important for the design.”

On the other hand, reduced charge mobility can limit the efficiency of electronic components, especially for applications that require high conductivity, such as power transmission lines or high-performance computing hardware. On the other hand, this localization effect could guide the design and development of sensitive sensors, phase change devices, ferroelectric devices, thermoelectric devices, and certain quantum devices.

“Our research provides the basis for engineered materials like tellurene to balance these tradeoffs,” Huang said. “This provides valuable insights for designing thinner, more efficient devices while addressing challenges arising from the unique behavior of low-dimensional materials, which is essential for the development of next-generation electronics and sensors. .”

Further information: Kunyan Zhang et al., Thickness-dependent polaron crossover in tellurene, Science Advances (2025). DOI: 10.1126/sciadv.ads4763

Provided by Rice University

Citation: Quasiparticle research unlocks new insights into tellurene, paving the way for next-generation electronics (January 14, 2025) https://phys.org/news/2025-01-quasiparticle-insights-tellurene Retrieved January 14, 2025 from -paving-gen.html

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