A collaboration between researchers at Princeton University and Rutgers University has led to the discovery of a new structure with the ability to turn topological behaviors on or off in quantum materials. This new discovery allows scientists to control how electricity flows in structures by engineering “artificial” materials.

Topological materials were the subject of the 2016 Nobel Prize in Physics. Topological insulators allow electrical current to flow with minimal resistance on their surfaces, but not through their bulk.

Led by M. Zahid Hasan, professor of physics at Princeton University, and Seongshik Oh, associate professor of physics at Rutgers University, the team designed a structure consisting of alternating layers of topological and normal (trivial), insulators. This architecture allowed the researchers to turn current flowing through the structure on or off. By controlling the current, new circuits based on topological behaviors could be designed. This system also provides an opportunity for studying the quantum behavior of artificial crystal lattice structures.

The discovery was recently published in the peer-reviewed journal, Science Advances. The article titled “A novel artificial condensed matter lattice and a new platform for one-dimensional topological phases,” dives into the architecture of their newly created structure, including why these materials matter in the burgeoning field of quantum materials.

In a Princeton blog post, principal investigator Zahid Hasan states: “This is an exciting new direction in topological matter research. We are engineering new topological states that do not occur naturally, opening up numerous exotic possibilities for controlling the behaviors of these materials.”

By controlling how electron-like particles called Dirac fermions move through material, researchers are a step closer in their ability to create superconductors that operate at higher temperatures, which could lead to more efficient electronics. Another possibility is the use of topological insulators for developing quantum computers. You can hear more from Dr. Hasan in this 100 Second Science video on the potential applications of topological insulators. To learn more about how scientists observe quantum behavior, check out this blog post by Forbes’ contributor Chad Orzel.

“In nature, whatever a material is, topological insulator or not, you are stuck with that,” Hasan said. “Here we are tuning the system in a way that we can decide in which phase it should exist; we can design the topological behavior.”

This isn’t the first time that Hasan and Oh have paired up to make new discoveries in quantum materials. In 2012, Hasan and Oh, along with other researchers, showed adding indium to a topological insulator, bismuth selenide, caused it to become a trivial insulator. This advance played an essential role in the development of the new structure.

The work was supported in part by the foundation’s Emergent Phenomena in Quantum Systems Initiative (EPiQS), which aims to promote discovery of new emergent electronic properties in materials. Topologically ordered materials are an important area of research within EPiQS, as they provide new insights into the basic organizing principles of complex matter and exhibit special electronic properties that may lead to practical applications. Both Hasan and Oh are Moore Investigators in Quantum Materials.


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