NSF-BSF: Chiral interactions in superconducting-magnetic junctions

University Of Chicago, Chicago IL

Investigators

Abstract

Non-technical abstract: The next generation of computing systems requires an efficient high-density memory with low power consumption. While magnetic bits are highly common, interconnects between bits are lossy. To reduce energy loss, it is necessary to change the material properties of interconnects. This project studies entirely new types of connections between magnetic bits, specifically by combining superconductors, magnets, and chiral molecules. This combination can create an unusual electronic state that enables near lossless interactions between bits. Such interconnects can then be implanted in the next generation of magnetic classical and quantum logic circuits. The proposed research relies on the proven expertise of three PIs that have overlapping and complementary skill in measurements, device fabrication, and local-probe studies, and who will work in tight coordination to achieve research goals. The proposed work will foster international collaborations and cooperation, particularly for students at all levels. High-school students and teachers will be integrated into the research, graduate students will gain experience in translation and international collaboration, and the PIs will work toward creating and implementing best-practices for greater inclusivity in research, especially considering international perspectives. Technical abstract: The project focuses on studying spin manipulation and control via interactions between chiral molecules (ChMs), ferromagnets, and superconductors, and on the integration of these three components for superconducting-spintronic applications. Spin-selective electron transport is typically associated with the use of magnetized materials, a process that is usually highly dissipative and of low efficiency. A drastically new solution to the problem has emerged from the discovery that ChMs function as spin-filters with surprisingly high efficiency, and thus transport through them is spin-selective. Moreover, recent works from the PIs reveal that adsorbing ChMs on various materials leads to spin manipulation. This project will examine the basic principles of chiral interactions in superconducting-magnetic junctions with the goal of improving interconnects between magnetic bits. This system generates a surface triplet state that may reduce spin phase decoherence. Specific studies will include exploring phase coherence using the Aharonov-Bohm and Josephson effects, monitoring anomalous magnetoresistance in chiral-magnetic structures, and determining chirality-induced spin polarization effects. Using a judiciously selected combination of magnetic and superconducting materials over which ChMs will be adsorbed, the research will lead to a deeper fundamental and practical understanding of hybrid magnetic superconducting chiral systems, thus enabling one to manipulate, transfer and exploit magnetic information in these systems. The proposed research relies on the proven expertise of three PIs that have overlapping and complementary skills in transport measurements, chiral-spintronics device fabrication, and local-probe techniques, and who will work in close coordination to achieve research goals. 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.