CAREER: Exploring Nonlinear Electrodynamics from Topology and Correlation in Layered Quantum Materials

Boston College, Chestnut Hill MA

Investigators

Abstract

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Nontechnical Description: How a material responds to electric and magnetic fields determines its functionality and its usefulness in electronic and optical devices. Nonlinear processes allow for interesting phenomena with widespread applications. For example, an optical limiting material can be transparent at low light intensity but opaque at high (and potentially hazardous) intensity. This allows a user to see under normal conditions while protecting them from injury. Nonlinear electromagnetic materials can address growing demands for devices with new functionality and higher efficiency. This CAREER project aims to explore new forms of nonlinear electromagnetism that arise from the quantum properties of electrons in novel two-dimensional quantum materials. The low dimensionality gives rise to new quantum confinement effects that can enable highly efficient and tunable electronic devices for information and energy technologies. The PI will explore the physics of atomically-thin layered quantum materials by fabricating ultrathin electronic devices from layered 2D materials and studying their nonlinear electromagnetic response at low temperatures. The project intimately integrates research activities, student mentoring, educational plans, and outreach initiatives centered around quantum materials, physics, and technology. The principal investigator is particularly dedicated to addressing gender inequality in physics by promoting female researchers and cultivating a young and vigorous force reserve through initiative programs. This project is jointly funded by the Electronic and Photonic Materials (EPM) and the Condensed Matter Physics (CMP) programs of the Division of Materials Research (DMR). Technical Description: Nonlinear electromagnetic responses are the phenomena where materials respond nonlinearly to external electromagnetic fields. Recent advances uncovered deep connections between nonlinear electromagnetic responses and topological and Berry curvature properties of quantum matter, leading to an emerging field of topological nonlinear electromagnetism. In this nascent field many questions need to be addressed. For instance, what are the signature nonlinear responses of new topological states and how large can they be? What is the role of impurities and scattering in those processes? What is the role of Coulomb interactions? Can we use those responses to probe and manipulate emergent phases? This CAREER project aims to answer those questions by exploring the physics in atomically-thin layered quantum materials with controllable Fermi energy, band structures, symmetry, topology and electron interactions through electrostatic gating, van der Waals stacking and layer twisting. The investigator develops innovative fabrication methods to create ultrathin electronic devices from those materials and investigates their nonlinear electromagnetic properties in a home-built multi-functional magneto-transport/optics cryo-system with broadband electromagnetic excitation. Combining highly-tunable nonlinear materials with broadband excitation will permit exploration of previously inaccessible regimes in topological and correlated 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.