Atomically precise metal nanoclusters and their assemblies as ‘ideal’ quantum emitters

Abstract

Semiconductor and metallic nanoparticles have received significant attention across the scientific community in recent decades and have reached the point of commercial applications in areas as diverse as biological labeling and high-definition displays. One frontier area in which their use is now being tested is that of optical quantum computing. As it develops, this technology promises to revolutionize nearly every area of science. The field of photonics-based quantum computing and cryptography requires the development of thermally stable, single quantum state emitters. These are materials that emit a stream of identical photons on demand, such as when triggered by absorption of a photon or by an electrical impulse. The stringent design criteria for single quantum state emission in a multi-atom system demands exquisite control of numerous factors including material composition, electronic structure, and environment. The ideal emitters would be identical in all these aspects and relatively insensitive to their surroundings. Even more challenging is the creation and detailed characterization of assemblies of multiple identical emitters capable of rapid and low-loss electronic communication and collective behavior. To do so would be to approach the level of design precision characteristic of biological assemblies such as the photosynthetic apparatus. This has been a longstanding fundamental goal in the fields of synthetic chemistry and materials science. The proposed work is to develop a new class of materials: atomically precise metal nanoclusters (NCs) containing more than one element and having both a precise number of total atoms and atomic composition (Jin). We will fabricate and characterize unprecedented multi-element NCs, and their assemblies to achieve new capabilities of single-atom, single-electron tailoring of properties, and will deliver a set of design rules for precise structure-function relationships for quantum technologies. Our expertise in optical microscopy (Peteanu) will enable us to investigate the photophysical behavior of single NCs and NC arrays with respect to photon correlation, emission coherence, and energy transfer. The effects on quantum emission of composition, size, and shape of NCs, as well as NC spacing, arrangement, will be probed. Critical to this effort is the structural characterization of the proposed NCs and NC assemblies made possible by atomic electron tomography (Dickey). This method provides atomic-level resolution without the need for NC crystallization, thus providing a path for rapid prototyping of candidate structures and detailed information on their degree of uniformity. Overall, the research thrusts provide an integrated program of activity that will create the knowledge to rationally design atomically precise NCs and NC assemblies that display targeted properties and functionalities, specifically for materials in quantum computing and cryptography.

Award amount: $300,000

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