Nanoscale Control of Individual Nitrogen-Vacancy Centers and Their Mutual Coupling by Magnetic Tunnel Nanojunctions

About This Grant

The past decade witnessed significant progress in quantum information science (QIS), an emerging discipline of modern scientific studies whose research interest is driven by saturation of downscaling and speeds of conventional information technologies. A grand strategy of the fast-advancing QIS is to harness intrinsic quantum mechanical properties of qubits to push the performance on information processing density, speeds, reliability, and energy-efficiency to the next level. Nitrogen-vacancy (NV) centers, optically active spin defects in diamonds, naturally stand out as a leading qubit candidate in this revolutionary quantum era and are finding increasing applications in QIS thanks to their excellent quantum properties under a broad range of experimental conditions. In this project, the principal investigator plans to integrate NV centers with on-chip magnetic nanodevices to develop hybrid quantum spintronic platforms to improve the scalability, electromagnetic tunability, and solid-state compatibility of NV centers for implementing transformative QIS innovations. In parallel with the proposed research topics, education, training, and outreach programs will also be included as an integral part of this proposal. A major effort will be dedicated to increasing society’s awareness of some of the most exciting developments and challenges in spintronics, quantum sensing, and novel computing technologies. It will promote participation of students, at both graduate and undergraduate levels, in the frontier of modern scientific research. Proposed outreach activities include lectures, workshops, learning and demo materials for local technical colleges, so that contemporary scientific knowledge can reach out to a significant amount of audience. Recently, NV centers, optically active spin defects in diamonds, have emerged as an appealing qubit platform for developing a range of cutting-edge quantum technological innovations. Taking advantage of the excellent quantum coherence, to date, this approach has been successfully applied to quantum metrology, sensing, and quantum-network research, showing remarkable field (spatial) sensitivity and extraordinary qubit operation merits. Despite the enormous progress made thus far, experimental demonstrations of NV-based quantum computing remain elusive in the current state-of-the-art. The major technical challenges center on how to locally address individual NV centers in a scalable, energy-efficient way, and precise control of NV-NV interaction at the nanoscale for large scale, high-density, and solid-state compatible quantum operations. This project aims to timely address these problems. Specifically, the principal investigator plans to introduce magnetic nanojunctions to achieve electrical voltage control of individual NV centers on a length scale down to ~50 nm. By synchronizing individual electron spin resonance frequencies and Rabi oscillations of two interacting NV centers (separated by 50 nm) by magnetic nanojunctions, this project proposes to realize electrical engineering of NV-NV dipole coupling and the overall two-qubit coherence performance for designing advanced quantum entanglement applications. The proposed research will promote the role of solid-state spin defects and magnetic nanodevices in advancing the forefront of quantum spintronic research and a broad range of emerging technological applications. The proposed quantum sensing study will further open a new perspective to investigate microscopic electromagnetic properties of nanoelectronics, which can be extended readily to many other device systems and benefit the community in the long run by impacting future quantum technologies. 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.