New Superconducting Interfaces for Quantum Technologies
Electrons in certain situations may pass through a potential barrier even though they lack the energy required to overcome the barrier according to the rules of classical mechanics. This event is called quantum tunneling, and it can give rise to superconducting interfaces, in which superconductors occur at the interface of two distinct materials. Correctly engineered and calibrated, superconducting interfaces could host Majorana bound states and exhibit perfect Andreev reflection—two tunneling phenomena with vast technological potential.
Theoretically speaking, these phenomena stand on solid ground. But observations of Majorana bound states and perfect Andreev reflection in laboratory settings are difficult to verify due to limitations of the superconducting materials currently available to researchers. To realize the technological potential of these phenomena, Katja C. Nowack and Eun-Ah Kim, Physics—in collaboration with researchers at Harvard University and Stanford University—are pursuing new superconducting interfaces with a focus on overcoming interface band-bending and defects that degrade the interface transparency, both of which limit current materials. The research team’s goal is to reproducibly realize Majorana bound states and perfect Andreev reflection at superconducting interfaces.
This research will develop a suite of theoretical tools to predict properties of interfaces. Using these novel tools combined with cutting-edge imaging and advanced electrical characterization methods, researchers will identify the most promising material candidates and will use state-of-the-art epitaxial growth to produce these materials with atomic precision. Potential applications of this research include high-performance topological quantum computers, quantum information processing, high-sensitivity sensors, and perfect spin filters.