Superconductors are already changing the world—for example, they’re powering MRI machines and high-speed maglev trains. New types of superconductors promise even more advances in energy, transportation, computing and many other fields. That’s why Dan Rhodes, an assistant professor in materials science and engineering at the University of Wisconsin-Madison, will use a National Science Foundation CAREER award to explore a theoretical type of superconductivity believed to take place at the edges of ultrathin, two-dimensional materials.
Superconductivity is a property of certain materials in which electrons are able to travel with zero resistance when they are subjected to extreme cold. This means electricity can flow through the materials without losing energy as heat, making them super-efficient conductors. They also expel magnetic fields, which allows the materials to levitate over magnets. When superconducting materials are fabricated as 2D materials—or materials that are just one atom thick—they take on even more interesting electrical and magnetic properties, making them potentially important in quantum computing and high-speed, efficient electronics.
Researchers believe that another superconducting state may also exist at the edges of certain 2D materials known as connate topological superconductors. “Usually, in a superconductor, the ordering of electrons is uniform across an entire material,” says Rhodes. “With topological superconductivity, a separate superconducting state forms along the edge of the material. So these two coexisting superconducting states give rise to a whole bunch of weird things.”
This unconventional superconducting state, however, has yet to be experimentally confirmed, something Rhodes hopes to do with this project. He plans to synthesize 2D topological semiconductors in a family called transition metal dichalcogenides. By applying special voltage and magnetic fields to the materials, he hopes to verify the existence of the topological superconducting state. From there, Rhodes says he would like to develop ways to electrostatically control this superconducting behavior.
“The point of this project is to create a system for searching for these new superconducting states,” says Rhodes. “And if it happens that this state exists in these materials, we can also say this is how to electrically control these materials. It will be an exciting path to travel down—and if we find something really, really cool (like what we expect to find), then that’s even better.”