CAREER: Optically Active Ensemble Defects in Monolayer Semiconductors for Magnetic Quantum Sensing

Nontechnical description Magnetic field plays an important role in technologies ranging from electronic devices and medical diagnostics to emerging quantum technologies. Detecting magnetic signals at extremely small length scales is essential for understanding quantum materials and biological processes, yet many sensing technologies struggle to detect magnetic interactions that occur over only a few atoms. In many current solid-state quantum sensors, the sensing defects are embedded inside bulk materials and are separated from the target system by several nanometers, which reduced sensitivity to short-range magnetic interactions. This CAREER project will investigate a new approach to magnetic sensing using atomically thin semiconductor materials that contain light-emitting defects. Because these materials consist of only a single atomic layer, the defects can be positioned extremely close to nearby magnetic systems, enabling highly sensitive optical detection of nanoscale magnetic behavior. The research will establish fundamental principles for magnetic sensing at atomic length scales and will contribute to quantum sensing technologies relevant to quantum information science and quantum materials research. This project integrates research with education by training students in quantum materials and optical spectroscopy while advancing workforce development in quantum science and engineering. Research outcomes will be incorporated into the University of Delaware’s Quantum Science and Engineering curriculum through the development of virtual demonstration modules that illustrate principles of quantum sensing. Simplified versions of the modules will be adapted for outreach activities with undergraduate and K-12 students. Students will also participate in structured science communication activities and a pilot industry training activity. Technical description Quantum sensing using solid-state defects has enabled highly precise measurements of physical quantities such as temperature, pressure, strain and magnetic field. However, most existing sensing platforms rely on defects in bulk crystals that are embedded several nanometers below the material surface. This separation limits sensitivity to short-range magnetic interactions and restricts the ability to probe interfacial magnetic phenomenon. This project will investigate a fundamentally different sensing platform based on chalcogen vacancy defects in monolayer transition metal dichalcogenide semiconductors. Because these semiconductors are atomically thin, the defect states can be placed in direct proximity to target materials, enabling magnetic sensing at nanometer and sub-nanometer length scales. The research team will introduce defects into monolayer semiconductors through thermally driven processes and will systematically study their optical and spin behavior using magneto-optical spectroscopy. Measurements will be performed on both non-magnetic and magnetic substrates to isolate proximity-induced magnetic interactions. By assembling semiconductor and magnetic heterostructures using van der Waals stacking, the team will investigate tunable interfacial magnetic coupling while preserving optical addressability at practical operating temperatures. Optical spectroscopy techniques will probe changes in defect emission energy, polarization and recombination dynamics in response to magnetic interactions. These studies will establish fundamental principles governing proximity-based magnetic sensing in two-dimensional materials and will advance understanding of defect physics and interfacial magnetism in quantum materials. The research activities will be closely integrated with education and training initiatives that prepare students to work at the intersection of quantum materials, optical spectroscopy, and quantum sensing technologies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual mer NSF Award ID: 2543219 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT,01002930DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Chitraeema Chakraborty | Institution: University of Delaware, NEWARK, DE | Award Amount: $401,476 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2543219 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2543219.html