Peterson publishes two high-impact studies on electromagnetic device materials
Christopher “Kitt” Peterson (PhD EE ’20) recently achieved publication in the prestigious research magazine Science. His article, “A fractional corner anomaly reveals higher-order topology,” is the result of work from an on-going study on topological insulators led by MechSE associate professor Gaurav Bahl and physics professor Taylor Hughes.
The research team was able to observe the signature of fractional electron charges in two-dimensional topological crystalline insulators by experimentally measuring their local density of states. Their measurements revealed one-fourth and one-third fractionalization, enabling the team to introduce a topological indicator that allows for the unambiguous identification of higher-order topology.
Peterson completed his bachelor’s degree in electrical engineering at Georgia Tech before connecting with Bahl, who was looking for someone with experience in microwave circuitry. As a junior, Peterson had taken a class called “Antenna Engineering” that sparked his interest in modeling signals. He had the opportunity to do research with his professor from that class the following year.
“I realized that doing this kind of research was something I wanted to pursue as a career, so I decided to go for a PhD,” Peterson said.
His experience came in handy for the study, for which the research team constructed specially designed microwave resonator circuits that mimic solid-state electronic topological insulators. The microwave circuits proved easier to experiment on, giving the team unprecedented access to previously unavailable features such as fractional charge.
The ongoing evolution of topological indicators is significant because electromagnetic devices typically experience some level of fabrication defects and tolerances that can negatively affect performance. Damage sustained from the wear and tear of normal, ongoing operation can also decrease performance and result in the need for replacement parts. However, the robust conductive channels that appear at the boundaries of topological indicators pose a promising solution to these needs, as these channels are able to remain in pristine condition despite damages sustained by the material and could thus protect wave transmissions from degradation.
“Higher-order topological insulators are a recently discovered class that host the same protected conductive channels at the intersections, or corners, of boundaries, which can greatly expand the possibilities for robust technologies,” Peterson said. “The goal of our work is to bring the promise of more efficient and robust devices based on topological concepts closer to reality.”
Following his recent publication, Peterson has another article currently under review that will expand on the concepts outlined in Science by investigating fractional charges trapped at lattice defects—i.e. inside the insulating material instead of at the boundary.
Reflecting on the journey to getting his first graduate research project published, which took multiple years and many revisions, Peterson urged incoming graduate students to persevere. “I think the most important thing is to not get discouraged if things aren’t going well,” he said. Peterson defended his PhD last month and will be joining the Georgia Tech Research Institute Advanced Concepts Laboratory in August.