Project Grant 2624415

ECCS-EPSRC: ELECTRICAL READOUT FOR SUB-DIFFRACTION IMAGING WITH HBN SPIN CENTERS -QUANTUM SENSORS CAN MEASURE MAGNETIC FIELDS, TEMPERATURE, AND OTHER PHYSICAL SIGNALS WITH EXTRAORDINARY PRECISION, ENABLING ADVANCES IN AREAS RANGING FROM BIOMEDICAL DIAGNOSTICS TO NEXT-GENERATION ELECTRONICS. MANY OF THE MOST POWERFUL QUANTUM SENSORS ARE BASED ON NANOSCALE SOLID-STATE SPIN DEFECTS?ATOMIC-SCALE QUANTUM OBJECTS THAT BEHAVE LIKE ARTIFICIAL ATOMS AND WHOSE QUANTUM STATES ARE EXQUISITELY SENSITIVE TO THEIR LOCAL ENVIRONMENT. THE MOST MATURE OF THESE ARE BASED ON DEFECTS IN DIAMOND THAT ARE READ OUT OPTICALLY, A METHOD THAT LIMITS SENSITIVITY, MINIATURIZATION, AND IMAGING RESOLUTION. THIS PROJECT WILL DEVELOP A NEW CLASS OF QUANTUM SENSORS BASED ON SPIN DEFECTS IN HEXAGONAL BORON NITRIDE, A TWO-DIMENSIONAL MATERIAL THAT CAN BE PLACED MUCH CLOSER TO THE OBJECT BEING MEASURED THAN EXISTING SENSOR TECHNOLOGIES. BY REPLACING CONVENTIONAL OPTICAL DETECTION WITH AN ELECTRICAL READOUT APPROACH, THE RESEARCH SEEKS TO OVERCOME FUNDAMENTAL LIMITATIONS IN CURRENT QUANTUM SENSING PLATFORMS AND ENABLE MEASUREMENTS WITH HIGHER SENSITIVITY AND FINER SPATIAL RESOLUTION. THIS PROJECT BRINGS TOGETHER THEORETICAL AND EXPERIMENTAL RESEARCH TEAMS IN THE UNITED STATES AND UNITED KINGDOM TO ACCELERATE THE DEVELOPMENT OF NEXT-GENERATION QUANTUM SENSING TECHNOLOGIES. BY COMBINING ADVANCES IN QUANTUM THEORY, MATERIALS DESIGN, DEVICE FABRICATION, AND PRECISION MEASUREMENTS, THE COLLABORATION WILL ESTABLISH A POWERFUL FEEDBACK LOOP IN WHICH THEORETICAL PREDICTIONS GUIDE EXPERIMENTS AND EXPERIMENTAL DISCOVERIES INFORM NEW THEORETICAL DIRECTIONS. IN THE LONG TERM, THE RESULTING SENSING CAPABILITIES COULD ENABLE TRANSFORMATIVE APPLICATIONS IN FIELDS RANGING FROM QUANTUM INFORMATION TECHNOLOGIES AND ADVANCED ELECTRONICS TO ENERGY-EFFICIENT DEVICES, BIOMEDICAL IMAGING, AND THE CHARACTERIZATION OF NOVEL MAGNETIC MATERIALS. BEYOND ITS SCIENTIFIC AND TECHNOLOGICAL IMPACT, THE PROJECT WILL STRENGTHEN TRANSATLANTIC RESEARCH PARTNERSHIPS, PROVIDE INTERDISCIPLINARY TRAINING FOR GRADUATE STUDENTS AND POSTDOCTORAL RESEARCHERS, DEVELOP OPEN-SOURCE SOFTWARE TOOLS FOR THE BROADER COMMUNITY, AND ESTABLISH A QUANTUM SENSING SUMMER SCHOOL THAT FOSTERS INTERNATIONAL COLLABORATION AND BROADENS PARTICIPATION IN QUANTUM SCIENCE AND ENGINEERING. TOGETHER, THESE ACTIVITIES WILL HELP BUILD THE EXPERTISE, INFRASTRUCTURE, AND GLOBAL PARTNERSHIPS NEEDED TO REALIZE THE FULL POTENTIAL OF EMERGING QUANTUM TECHNOLOGIES. THIS PROJECT WILL ESTABLISH A NEW QUANTUM SENSING PLATFORM BASED ON ELECTRICALLY READABLE SPIN DEFECTS IN HEXAGONAL BORON NITRIDE INTEGRATED WITHIN GRAPHENE?HEXAGONAL BORON NITRIDE?GRAPHENE VAN DER WAALS HETEROSTRUCTURES. THE CENTRAL OBJECTIVE IS TO DEMONSTRATE ROOM-TEMPERATURE QUANTUM SENSORS WITH MAGNETIC-FIELD SENSITIVITY AND SPATIAL RESOLUTION EXCEEDING THE CURRENT STATE OF THE ART FOR HEXAGONAL BORON NITRIDE DEFECT SENSORS. IN THE FIRST RESEARCH THRUST, THE TEAM WILL DEVELOP AND OPTIMIZE HETEROSTRUCTURE DEVICES IN WHICH SPIN-DEPENDENT RESONANT TUNNELING CURRENTS PROVIDE AN ELECTRICAL MEASURE OF DEFECT SPIN POLARIZATION, ENABLING EFFICIENT ELECTRICAL DETECTION OF MAGNETIC RESONANCE. A TIGHTLY INTEGRATED THEORETICAL?EXPERIMENTAL FRAMEWORK WILL BE USED TO INVESTIGATE CHARGE TRANSPORT, SPIN DYNAMICS, NOISE PROCESSES UNDER ELECTRICAL READOUT, AND TO OPTIMIZE DEVICE DESIGN AND READOUT PROTOCOLS. IN THE SECOND THRUST, ELECTRICAL READOUT WILL BE COMBINED WITH SUPER-RESOLUTION OPTICAL MICROSCOPY TECHNIQUES TO ACHIEVE MAGNETIC IMAGING WITH SPATIAL RESOLUTION BELOW THE DIFFRACTION LIMIT. THESE CAPABILITIES WILL BE BENCHMARKED THROUGH IMAGING OF MAGNETIC VORTICES, SKYRMIONS, AND DOMAIN STRUCTURES IN EMERGING MAGNETIC MATERIALS. IN THE THIRD THRUST, THE PROJECT WILL DEVELOP A PROTOTYPE ALL-ELECTRICAL SPIN IMAGING DEVICE, CONSISTING OF MULTIPLEXED ARRAYS OF NANOSCALE SENSING PIXELS THAT PERFORM MAGNETIC IMAGING THROUGH PARALLEL ELECTRICAL READOUT CHANNELS, ELIMINATING THE DIFFRACTION-LIMITED CONSTRAINTS OF CONVENTIONAL OPTICAL APPROACHES. THE ANTICIPATED OUTCOMES INCLUDE A COMPREHENSIVE UNDERSTANDING OF ELECTRICAL SPIN READOUT IN TWO-DIMENSIONAL MATERIALS, SUBSTANTIALLY IMPROVED QUANTUM-SENSING PERFORMANCE, NEW METHODOLOGIES FOR NANOSCALE MAGNETIC IMAGING, AND SCALABLE DEVICE ARCHITECTURES FOR FUTURE QUANTUM TECHNOLOGIES. THE PROPOSED WORK WILL ADVANCE FUNDAMENTAL KNOWLEDGE IN QUANTUM SENSING, SPIN PHYSICS, LOW-DIMENSIONAL MATERIALS, AND QUANTUM DEVICE ENGINEERING WHILE PROVIDING A PATHWAY TOWARD COMPACT, MANUFACTURABLE QUANTUM MAGNETOMETRY SYSTEMS. 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.- SUBAWARDS ARE NOT PLANNED FOR THIS AWARD.