Quantum Science and Engineering at Cornell
Cornell’s Ithaca campus is home to a broad range of investigations into the quantum-mechanical nature of our world and universe, as well as the study of how to harness effects that are uniquely quantum mechanical for producing new technology in computing, communication, and sensing.
This website serves as a central source of information about who is working on quantum science and engineering at Cornell, what research areas we cover, and what quantum-related events are taking place.
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News and Breakthroughs
Electrical sliding switches graphene between magnetic states
In a discovery that could offer a new way to control quantum properties in two-dimensional materials, researchers at Cornell have found that electrically sliding the layers of ultrathin graphene can switch the material between distinct magnetic states that persist even after the voltage is removed.
Researchers in the lab of Kenji Yasuda, assistant professor in the School of Applied and Engineering Physics in Cornell Duffield College of Engineering, discovered that when voltage was applied to a four-layer graphene stack, the layers slid into different atomic stacking arrangements, allowing the material to alternate between nonmagnetic and magnetic states, according to the study, published Oct. 14 in Nature Nanotechnology.
A new ingredient for quantum computing: krypton gas
To commercialize quantum computing, manufacturers need high-quality superconducting materials for microchips, but they also require a reliable, sustainable nanofabrication process.
Tantalum is a corrosion-resistant metal that meets the first criteria but not the second. That’s because it has to be deposited on a substrate at temperatures that typically exceed 400 degrees Celsius – too hot for many semiconductor foundries’ current tools.
Cornell researchers have developed a method that uses krypton gas to slash that deposition temperature to 200 degrees while depositing on silicon, a standard high-quality substrate. The process resulted in thin films that also have substantially higher electronic conductivity.
“Tantalum as a material has been shown to be very exciting from a device performance perspective, but its manufacturability had some question marks because of integration challenges such as required process temperatures,” said Valla Fatemi, assistant professor and Aref and Manon Lahham Faculty Fellow in the Cornell Duffield College of Engineering, who led the project.
Researchers break light symmetry with simple materials
Light typically interacts with a material the same way whether it enters through the front or the back – like polarized sunglasses that work the same from either side. Cornell researchers have demonstrated a simple route to breaking that symmetry, opening new possibilities for photonics and quantum information processing.
Optical reciprocity, the principle that a system responds identically regardless of which side faces the light, underlies most lenses, mirrors and other optical devices. A new study published July 27 in Nature Materials demonstrates that some materials can be engineered to exhibit nonreciprocal absorption and emission of linearly polarized light.
“Imagine window blinds with sunlight coming through its horizontal slats, but from the opposite side, the same blinds let light through as if the slats were vertical, completely inverted,” said corresponding author Richard Robinson, professor of materials science and engineering in the Cornell Duffield College of Engineering. “To get this type of behavior, you typically need complex metamaterials or external magnetic fields, but we show that it can be achieved in simple, solution-processed semiconductor nanoclusters.”
If you’re working on quantum research at Cornell and would like to contribute material to this website, please email quantum@cornell.edu.