TECHNOLOGY AREA(S): Materials, Electronics
OBJECTIVE: Establish approaches to fabricate with atomic-level precision strongly correlated electronic materials such as artificially created two-dimensional materials with Hubbard interactions and high temperature superconducting oxides.
DESCRIPTION: There is a compelling DoD need for new techniques for the fabrication of strongly correlated materials with atomic precision in order to enable better and faster comparison with theory as well as implement better platforms for the exploitation of their properties in devices. Strongly correlated materials, such as high temperature superconductors, have the potential to revolutionize technology if their properties (e.g., operating temperatures) can be improved. A poor understanding of the mechanisms by which these materials get their properties has hampered efforts in this direction. The inevitable presence of imperfections (defects, impurities) in conventionally fabricated materials exacerbates the problem. The manufacturing of materials with atomic precision has advanced considerably over the past few years. Bottom up fabrication processes like Scanning Tunneling Microscope Lithography  have enabled the fabrication of high quality graphene nanoribbons  and even the implementation of quantum bits using donor defects . While such developments demonstrate the potential for this technology, such processes have not yet been extended to the fabrication of strongly correlated materials. This topic seeks innovative solutions to the implementation of processes for the fabrication of strongly correlated materials with atomic precision. Such processes and techniques will enable the development of novel materials as well as enhance our understanding of their physics.
PHASE I: Develop approaches that will extend state of the art atomically precise fabrication techniques for two-dimensional materials. Design key metrics for the proposed materials (e.g. atomic placement accuracy, system size). Perform a study assessing the scalability of the process and the ability to implement in various platforms and for the fabrication of different kinds of materials. Perform a proof of principle demonstration that validates the proposed concept. Required Phase I deliverables will include a final report detailing the results of the study and proof of principle demonstration. The report should also list the potential materials that may be compatible with the proposed process. For this topic, DARPA will accept proposals for work and cost up to $225,000 for Phase I. The preferred structure is a $175,000, 12-month base period, and a $50,000, 4-month option period. Alternative structures may be accepted if sufficient rationale is provided.
PHASE II: Implement the approach developed during Phase I and demonstrate the ability to fabricate strongly correlated materials with atomic precision. Evaluate and characterize the fabricated materials against the proposed design metrics and validate the presence of strongly correlated electronic effects in the materials. Required Phase II deliverables will include a final report and samples of the fabricated materials that may be tested at a government specified laboratory for validation.
PHASE III: The fabrication of strongly correlated materials with the process developed under this topic (with the required precision and production scale) will enable their implementation in various applications. For instance, high temperature superconductors may be useful in military and commercial systems, such as low-loss power generation and transmission, medical imaging and high efficiency computing.
1: J. N. Randall et al., "Atomic precision lithography on Si", J. Vac. Sci.Technol. B, 27, 2764 (2009)
2: A. Radocea et al., "Solution-Synthesized Chevron Graphene Nanoribbons Exfoliated onto H:Si(100)", Nano Lett. 17, 170 (2017)
3: Y. Wang et al., "Characterizing Si:P quantum dot qubits with spin resonance techniques", Scientific Reports 6, 31830 (2016)
KEYWORDS: Atomic Precision Fabrication, STM Lithography, Strongly Correlated Materials, Superconductors