Special Seminar: Short-Range Order in Semiconductor Alloys—From hidden correlations to materials design

Optional ZOOM LINK
Meeting ID: 920 4857 0988
Passcode: 362495

Materials that appear random or disordered often conceal hidden patterns that play a powerful role in determining their properties. One example is short-range order (SRO), subtle atomic-scale correlations that exist even within alloys thought to be completely random. While SRO has long been studied in metals, its significance in semiconductor alloys had remained virtually unknown.

In this seminar, I will highlight recent work that brings these hidden structures to light. Drawing inspiration from earlier studies of nucleation in ice and other complex systems where ordering often emerges within apparent disorder, we predicted that SRO should also exist in group-IV semiconductor alloys and strongly influence their electronic behavior. To probe this idea, we developed new modeling tools and partnered with advanced characterization techniques such as four-dimensional scanning transmission electron microscopy, atom probe tomography, and extended X-ray absorption fine structure. These efforts have now provided the first direct evidence that SRO exists in semiconductors and can dramatically alter their functional properties. The findings open the door to "SRO engineering": intentionally tuning local order to design new materials in ways that conventional approaches cannot achieve. This perspective has broad implications for energy-efficient electronics, neuromorphic architectures, and quantum technologies, illustrating how uncovering hidden order in complex systems can inspire entirely new directions in materials design.

About the Speaker(s)

Tianshu Li
Professor of Civil and Environmental Engineering, George Washington U

Tianshu Li is a professor in the Department of Civil and Environmental Engineering at George Washington University. He obtained his bachelor's and master's degrees in materials science and engineering from Tsinghua University in 1999 and 2001, respectively. He completed his PhD in materials science from University of California, Berkeley in 2005. From 2006 to 2010, Li continued his research as a post-doctoral associate in Department of Chemistry at University of California, Davis. He then joined the George Washington University faculty in 2010. Li's research is focused on modeling materials' behaviors using classical, quantum, and machine-learning approaches. His current research interests include understanding the thermodynamics and kinetics of crystal nucleation and unraveling complex structures and properties of materials.

Contact

For more information, contact Ashley Parker at ashley.l.parker@dartmouth.edu.