NSF-ANR QISE:Hexagonal Boron Nitride Quantum Sensors

Kansas State University, Manhattan KS

Investigators

Abstract

Sensors that use quantum effects can be more sensitive to motion and light, have higher spatial resolution, and be more accurate than other types of sensors. This project will focus on hexagonal boron nitride crystals (hBN), which are thin, chemically stable materials, that show great promise for improving the performance of quantum sensors. These sensors work by behaving like tiny magnets whose pole directions can be measured. While powders from hBN have a wide range of applications, including as a whitener in cosmetics, hBN crystals will be particularly useful for sensors because of their high purity and highly ordered arrangement of their atoms relative to other materials. This international collaborative project will grow hBN crystals, measure their optical properties, test their magnetic field sensing capabilities, and determine how the devices can be optimally structured. Ultimately, hBN quantum devices will find new medical applications, including the study of biological processes, virus identification and diagnostics, and discovering new drugs. This project will provide students the opportunity to engage with science and technologies that can benefit society including crystal growth, material characterization, and quantum devices. Both the Kansas State University and Centre National de la Recherche Scientifique groups will undertake outreach activities to intrigue and excite the public and students in the fields of quantum science and technology. Technical Abstract This project will experimentally investigate the methods for creating, and the properties of, optically detectable spin defects in hBN for quantum sensing of magnetic and electric fields. Freestanding, high quality (low intrinsic defect density) hBN crystals will be grown by precipitation from molten metal solutions. Boron vacancies will be created by nuclear transmutation. Carbon doping will be achieved during crystal growth by ion implantation. To gain a deep understanding of the fundamental properties of the defects and to optimize the quantum sensor sensitivities, hBN crystals with specific isotopes of boron, nitrogen, and carbon dopants will be studied. Defect energy states in the crystals will be established by deep ultraviolet photoluminescence (3 eV to 6.5 eV) and optically detected magnetic resonance (ODMR). Quantum devices will be fabricated, and their performance in detecting magnetic and electric fields tested and optimized. This project will address key questions for optimizing hBN quantum sensing including: (1) Which point defects, are most effective in quantum sensors? (2) What defect densities and defect configurations are needed to optimize device performance? (3) To what extent can quantum sensing be improved by employing hBN with specific boron and nitrogen isotopes? (4) Can the ultimate quantum sensing of magnetic and electrical fields be produced from hBN monolayers? A priority of this project is to train the next generation workforce in quantum information science and engineering. Students will learn about crystal growth, the optical characterization of materials, and quantum properties and applications. This project will strengthen the established international collaboration between KSU and CNRS. Both the KSU and CNRS groups will be involved in the outreach activities that are designed for the public and students from a wide range of groups. These activities will demonstrate the creative aspects and the collaborative nature of science, and the benefits of quantum science and technology to society. 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.