Solving the Best Puzzles

by Alan S. Brown

Dan Ralph, new co-director of the Kavli Institute at Cornell for Nanoscale Science, describes the strengths of the institute and what lies ahead

The Author

Alan S. Brown

At the Kavli Institute at Cornell for Nanoscale Science, researchers endeavor to develop next-generation tools to image, manipulate, and control objects at the nanoscale. From ultrafast optical imaging systems to electron microscope detectors that resolve individual atoms, Cornell's Kavli members have succeeded brilliantly in creating powerful new probes.

The Kavli Institute at Cornell (KIC) continues to be recognized for pushing nanoscience into new areas of inquiry. Advances range from nanoscale robots and agricultural sensors to exotic semiconductors, magnetic memories, and three-dimensional systems held together by van der Waals forces alone.

Yet, when asked what sets KIC apart from other research centers in the field, new co-director Dan Ralph emphasizes the institute's support of its community, particularly early career scientists.

"That's the most important part of our program," Ralph said. "We draw in the best young scientists in the world. They come with exciting new ideas and we give them the resources and equipment they need to try things out that they would not ordinarily be able to do. We give them an opportunity to really launch their careers, and they are recruited by some of the world's top research institutions."

This infusion of new talent and ideas aligns well with the institute's broad scope. While many scientific institutes focus on digging deep into a limited number of research areas, KIC seeks variety. Ten years after it was founded, it continues to pursue the broadest possible interpretation of nanoscience.

"We're constantly looking for new puzzles, new problems, and new areas of research that people haven't considered before. Some involve fundamental science questions while others are more about engineering, but they are all areas where research can make a difference."

Dan Ralph

Piecing the puzzle together

Puzzles are what drew Ralph to science in the first place. Growing up in Lexington, Kentucky, his parents were "more or less academics," he said. His father, a clinical psychologist, ran a psychiatric facility and his mother held a Ph.D. in English literature.

Those pursuits did not entice Ralph. Instead, he liked to solve puzzles. "Science seemed like a field with good puzzles and solving them might lead to something useful," he said. He gravitated to physics in college because he felt it tackled more fundamental questions. As a freshman, Ralph was inspired by an engaging physics teacher, "a Yoda-like character who was very good at posing problems that helped us understand what we were learning," he said.

After completing a Ph.D. at Cornell University and a post-doctoral fellowship at Harvard University, he returned to Cornell to teach in 1996. He was attracted by the school's outstanding nanofabrication capabilities and its scientific community. "It's a collaborative culture and not a bunch of little kingdoms," he said. "People generally get along and try to be more than just the sum of the individual groups."

As an early member of the Kavli Institute at Cornell, Ralph continues to let curiosity drive his work, ranging from the use of electron spin to manipulate magnetic devices (used in recently commercialized memory devices) and the quantum properties of material defects and impurities to superconducting systems and new nanofabrication techniques.

And, as the institute's new co-director, the puzzles have only grown more varied.

Engineering innovation

Understanding the nanoworld is always challenging because events happen in billionths and trillionths of a second at infinitesimally small scales, often involving forces that go unnoticed in the world around us. KIC and Cornell are known for instrumentation capabilities with enough resolution to uncover secrets hidden at this scale, opening doors to new theories, new materials, and new devices.

Early on, KIC invested in fast optical microscopes that operate over a very broad range of wavelengths. Ralph's own research work has taken advantage of an apparatus with rotating magnets to study the dynamics of nanoscale magnetic devices. Ralph's co-director, David Muller, pioneered new innovations in electron microscopy to achieve unprecedented imaging at the atomic level. "This new generation of detectors allows types of imaging modes that have not been possible before," Ralph said. "We can not only see single atoms, but we can watch them as they vibrate in different directions due to thermal excitation."

KIC is also a leader in harnessing new materials and inventing unusual devices. One example is the nanorobots developed by former institute director Paul McEuen and Itai Cohen. By using origami techniques to cut and fold ultrathin bimetal sheets to form legs and wedding them with microscopic slivers of semiconductor electronics, they have created ultrasmall robots that can move and take measurements.

"These untethered instruments could potentially do lots of useful things, such as diagnosing illness in the body," Ralph said. "And building them poses many interesting materials challenges, such as how to incorporate various heterogeneous materials into small scale structures and have them all work together. It's not easy to add actuators and sensors to silicon at high temperatures without messing up the silicon."

These advances represent only a small sampling of KIC's range, and Ralph hopes to learn more as he grows into his role as co-director. But he is certain about one fact: "In terms of science, there is no specific theme or collective vision tying them all together. Instead, there are lots of little pieces moving in different directions that are, collectively, very exciting.”

Embracing variety

Because the institute defines nanoscience so broadly, it often attracts surprising proposals. "I'm excited about one recent research proposal that involved nanosensors for plant biology and agriculture," Ralph said. "If you think about it, we have ways to measure things like blood pressure and temperature, so we know exactly what is going on with people and animals. But there hasn't really been a way of doing the same thing for plants so we can learn what makes them thrive.” Building those sensors, an effort being led by Dr. Abraham Stroock, is another exciting new area at KIC.

KIC uses several strategies to keep the fresh ideas flowing. One is to build collaboration into postdoctoral fellowships. Fellows at KIC identify at least two faculty members as sponsors, and utilize both scientific and social get-togethers to circulate ideas from different disciplines throughout the institute's laboratories.

Another approach is to diversify voices in leadership. In 2022, in anticipation of the institute’s 10-year anniversary and eager to bring in new ideas for future directions, KIC held a series of meetings to consider opportunities and invited diverse participants to attend. Those with great ideas and enthusiasm were invited to join the executive committee. The hope is that these new voices will lead KIC in surprising and challenging new directions.

Dan Ralph would not want it any other way.