A team of scientists led by physicist Peng Wei at the University of California, Riverside, has developed a new superconductor material that has potential applications in quantum computing. This material could be a candidate for a “topological superconductor,” which uses a delocalized state of an electron or hole to carry quantum information and process data in a robust manner. The researchers combined trigonal tellurium with a surface state superconductor generated at the surface of a thin film of gold. Trigonal tellurium is chiral and non-magnetic, and the researchers observed quantum states at the interface that host well-defined spin polarization, which could be used to create a spin quantum bit, or qubit.
By creating a clean interface between the chiral material and gold, the researchers developed a two-dimensional interface superconductor with enhanced spin energy compared to traditional superconductors. The interface superconductor exhibited transition under a magnetic field, becoming more robust at high field compared to low field, suggesting a transition into a “triplet superconductor” that is more stable under a magnetic field. Collaborating with scientists at the National Institute of Standards and Technology, the researchers showed that this superconductor involving heterostructure gold and niobium thin films can suppress decoherence sources from material defects, which is a common challenge in niobium superconductors. The superconductor can also be made into high-quality low-loss microwave resonators with a quality factor reaching 1 million.
The new technology has applications in quantum computing, a field that leverages quantum mechanics to solve complex problems that classical computers or supercomputers cannot handle efficiently. This technology uses materials that are thinner than those typically used in quantum computing, and the low-loss microwave resonators it produces are critical components that could lead to low-loss superconducting qubits. The biggest challenge in quantum computing is reducing decoherence, or quantum information loss in a qubit system, which occurs when a quantum system interacts with its environment. The researchers’ approach uses non-magnetic materials for a cleaner interface, offering a promising candidate for developing more scalable and reliable quantum computing components.
The research paper, titled “Signatures of a Spin-Active Interface and Locally Enhanced Zeeman Field in a Superconductor-Chiral Material Heterostructure,” details the findings of the study. The UCR contribution to the project was funded by NSF grants, including Wei’s NSF CAREER award and a NSF Convergence Accelerator Track-C grant shared by UCR and MIT, as well as a Lincoln Lab Line fund shared by UCR and MIT. The technology has been disclosed to the UCR Office of Technology Partnerships, and a provisional patent has been filed. The University of California, Riverside is a doctoral research university that serves as a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state, and communities around the world. With a diverse culture reflected in its enrollment of over 26,000 students, UCR has an annual impact of more than $2.7 billion on the U.S. economy.