EAGER: SUPER: Carbon-based Superconductors Stable at Ambient Temperature and Pressure

University Of Illinois At Chicago, Chicago IL

Investigators

Abstract

NON-TECHNICAL SUMMARY The existence of superconductors - materials that conduct electricity without resistance - at conditions of the Earth’s surface would revolutionize diverse technologies ranging from the electrical grid to computing and communications. New materials displaying superconductivity at or near room temperature have been discovered but they are stable only at very high pressures, such as found within the core of the Earth. The paramount challenge, both fundamentally and for eventual applications, is stabilizing these and related superconducting materials at ambient pressure. This project, supported by the Division of Materials Research at NSF, addresses this challenge through integrated theoretical calculations and experiments to examine previously unexplored chemical compositions, with a focus on carbon-rich materials. The guiding hypothesis is that structures in which carbon has the bonding properties of diamond could lead to room-temperature superconductivity at ambient pressure. Carbon-rich compounds are systematically explored using synthesis at high pressures and temperature in combination with both simultaneous characterization and sophisticated computations to interpret and guide the experiments. The project involves education and training of undergraduate students from the diverse population of the University of Illinois at Chicago (UIC). The success of this research would lead to important advances in basic science, create potential for major shifts in technology, and train the next generation of scientists, including groups underrepresented in STEM fields. TECHNICAL SUMMARY The quest for materials that exhibit superconducting critical temperatures near ambient conditions has been a long-sought goal of condensed matter physics, which among others, could be key to quantum information technology. Guided by increasingly accurate predictions of targeted chemical compositions using density functional theory, high-pressure experiments have demonstrated the existence of superconductivity at record high temperature in hydrogen-rich materials. Replacement of hydrogen with carbon in some of these materials is predicted to give rise to high critical temperature in structures that can be preserved on decompression, owing to their rigid carbon frameworks, which impart kinetic stabilization at ambient conditions, much like for diamond. This project, supported by the Division of Materials Research, will involve an interdisciplinary team at UIC to carry out an accelerated exploration of carbon-rich phases, beginning with light alkali metal-containing materials, using in situ x-ray diffraction with heating and pressurization, measurements of superconductivity, and tests of kinetic stability at or near ambient pressure. The experiments are integrated with and informed by DFT and other theoretical calculations, augmented by machine learning approaches and other large data techniques. The UIC group incorporates the approaches developed in the project in university courses. Undergraduates from the diverse student population of UIC, a minority serving institution, take part in this research and education experience. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.