Collaborative Research: Twist Control of Correlated Physics in Two Dimensions

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Nontechnical DescriptionInnovations in materials science drive the creation of technologies that fundamentally alter how societies function. For years there has been excitement around the possibility of computers based on the principles of quantum mechanics. This dream remains unrealized both due to the lack of tunable quantum behaviors in materials and a pipeline for training a quantum-literate workforce. The main research objective of this project is to accelerate the production of next-generation technologies by achieving unprecedented control over the physics in quantum materials. The project will specifically investigate atomically thin materials that individually have strong electronic interactions to understand how these interactions may be manipulated through layer engineering. This new ability to design quantum states by twisting layers can hasten the creation of memory and computing technologies that are superior in performance and energy efficiency to the status quo. Twist angle physics in quantum materials also provides new insight into how interactions between electrons can lead to unexpected behaviors. The education goal of this project is to build a quantum-literate workforce by teaching high school and undergraduate students about possible career paths in quantum technology as well as how to follow these paths. Quantum workforce development is carried out through cross-institution, academia-industry events that include: 1) a ‘Careers in Quantum’ event where students can directly interact with industry experts, 2) outreach events at the Principal Investigators’ institutions, and 3) a middle school science camp. These activities are poised to make a long-standing impact in the preparation of students for exciting careers in an increasingly quantum high-tech industry.Technical DescriptionThe objective of this project is to discover the role of interlayer interactions in layered quantum materials through the exploration of twisted heterostructures of tantalum disulfide. Existing studies of layered quantum materials demonstrate connections between electronic ground state and layer alignment, but these are limited to a small set of naturally occurring stacking configurations and wrought with contradictions. By leveraging twist-tunable heterostructures and a range of characterization and modeling that spans nanoscale to mesoscale physics, this project systematically explores strongly correlated physics in tantalum disulfide to uncover the total phase space detailing the interplay of Mott physics, charge density waves, magnetism, and metallic states. This research is enabled through a partnership between the University of New Hampshire and George Mason University and with the Quantum Material Press at Brookhaven National Laboratory. The central research activities are: 1) creating the first twisted heterostructures comprised of strongly correlated materials; 2) elucidating the twist-angle structure-property relationships in tantalum disulfide through the correlation of nanoscale scanning tunneling microscopy and mesoscale magneto-Raman spectroscopy; and 3) discovering the impact of aperiodicity in a new class of twisted quantum quasicrystals. Experimental results from these efforts can inform the creation of theoretical models of twist physics by collaborators at the Naval Research Laboratory, leading to a more general understanding of quantum emergence in layered solids. The structure-property relationships established in this work provide a set of guiding principles for designer quantum behaviors in twisted heterostructures, such as switchable ground states, through the judicious choice of 2D material and layer orientation.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.