Quantum Heterostructures of Rhodates and Iridates with Tunable Electron-Correlation and Spin-Orbit Interactions

Non-technical abstract: This project will investigate new physical phenomena that emerge when quantum materials are stacked into ultra-thin layered structures known as heterostructures. These are made by combining crystals such as iridium, ruthenium, and rhodium oxides, which interact in unique ways at their atomic interfaces. These interactions can lead to novel electronic and magnetic properties not found in the individual materials. The research will focus on tuning two key quantum effects, electron correlation and spin-orbit interaction, to uncover exotic behaviors with potential relevance to future quantum technologies. Using advanced techniques, the team will probe how electrons behave in these custom-designed materials. In addition to advancing scientific knowledge, the project will train both undergraduate and graduate students in state-of-the-art materials synthesis and spectroscopy. It also includes outreach programs for high school students and future teachers, supporting science education and inspiring interest in physics and materials science. Technical abstract: This project investigates emergent quantum phases in heterostructures composed of 4d rhodates and ruthenates and 5d iridates, where strong electron correlation (U) and spin-orbit interaction (SOI) coexist and compete. These systems offer a unique platform for tuning key physical parameters such as bandwidth, dimensionality, and lattice symmetry through interface engineering. It also enables controlled exploration of correlated spin-orbit coupled ground states. The central goal is to determine how interfacial charge transfer and doping modulate the coupling of U and SOI, leading to novel electronic and magnetic interfacial states. Epitaxial thin films and heterostructures will be synthesized via pulsed laser deposition with in-situ optical spectroscopic ellipsometry and reflection high-energy electron diffraction, providing atomic-scale control. Advanced spectroscopic techniques, including resonant inelastic X-ray scattering, Raman spectroscopy, and infrared spectroscopic ellipsometry, will be used to probe spin excitations, orbital dynamics, and charge behavior. These experiments will be coupled with theoretical modeling to uncover the microscopic mechanisms underlying emergent phases. By bridging experiment and theory, this project will establish a tunable model platform for investigating strongly correlated quantum matter at 4d/5d interfaces. 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.