CAREER: Towards a Unified Optical View of Strong Correlation in Moire Quantum Matter

Non-technical Abstract: This project studies new types of materials, known as moiré materials, created by stacking extremely thin layers of matter with precise alignment, leading to unusual and potentially useful electronic behavior. These materials can switch between conducting, insulating, and superconducting states - properties that are important for future technologies but remain poorly understood. The research combines optical and electrical measurements to probe how these materials respond to energy and heat at very small scales, providing insight into how their internal structure governs their macroscopic behavior. By exploring previously inaccessible regimes, the project opens new pathways for understanding and controlling these systems. The educational component closely integrates research with the training of undergraduate and graduate students through hands-on experience in nanofabrication, cryogenic measurements, and data analysis. The project also includes summer science camps for local middle- and high-school students, along with a publicly accessible video series that demystifies advanced materials and introduces young learners to modern physical science in an engaging and accessible way. Together, these research and education efforts help train the next generation of scientists and engineers in areas central to emerging technologies and materials innovation. Technical Abstract: This project addresses the scientific question of the microscopic origins of low-energy collective excitations and thermoelectric transport in moiré superlattices, where flat electronic bands and strong interactions dominate physical behavior, and examines how near-field microscopy can be used to directly probe these effects. The research focuses on twisted bilayer graphene and transition metal dichalcogenide moiré systems, with the goal of identifying how electronic structure and many-body effects govern plasmonic, optical, and thermoelectric responses. The research team employs cryogenic near-field optical microscopy combined with mid-infrared and terahertz photovoltage imaging to measure collective excitation dispersions and correlated charge dynamics with nanoscale spatial resolution. Complementary electronic transport and thermoelectric measurements enable direct comparison between optical and electrical responses, providing quantitative insight into interaction-driven renormalization effects. The scope of the research includes mapping hybridized plasmon and phonon modes in graphene moiré lattices and identifying thermoelectric signatures of charge ordering, scattering mechanisms and melting transitions in transition metal dichalcogenide superlattices. Through these approaches, the project establishes a unified experimental framework for connecting nanoscale electrodynamics to emergent quantum phases in two-dimensional moiré materials. The educational component of this project is tightly integrated with the research program, providing undergraduate and graduate students with hands-on training in nanofabrication, cryogenic measurements, and quantitative data analysis. Experiential learning is complemented by targeted outreach activities, including summer quantum science camps for middle- and high-school students and the development of a publicly accessible educational video series designed to communicate key concepts in quantum materials to a broad audience. Collectively, these efforts establish a comprehensive training and outreach framework that advances workforce development in areas aligned with national priorities, including emerging technologies and advanced materials. 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. NSF Award ID: 2542595 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT,01003031DB NSF RESEARCH & RELATED ACTIVIT,01002930DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Petr Stepanov | Institution: University of Notre Dame, NOTRE DAME, IN | Award Amount: $407,064 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2542595 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2542595.html