CAREER: Designing and Probing Emergent Phases with Tunable Magnons in Graphene

Non-technical abstract

Magnons are quantum mechanical, wave-like objects in magnetic materials that display fundamentally different characteristics than electrons. Harnessing magnons presents an intriguing avenue for creating synthetic matter not found in nature and developing next-generation quantum devices with unprecedented functionalities. While the properties of electrons have been intensively studied, the investigation of magnons and their collective behavior in solids remains extremely limited.

A promising and tunable platform to explore this direction is graphene - a sheet of carbon atoms - placed in a strong magnetic field, where magnons can be efficiently launched and detected. The primary goal of this project is to explore the possible quantum phenomena that can be engineered by using magnons as building blocks and to investigate the feasibility of utilizing magnons to probe the magnetic properties of atomically thin materials.

The success of this project promises to advance the frontier of fundamental quantum science and enable innovative pathways to future quantum technologies such as ultra-low-power information devices. This project also connects materials education with the growing societal demand for quantum technology through research-informed education and outreach programs for high school, undergraduate, and graduate students.

Technical Abstract

The exploration of correlated and topological states of charge-neutral bosons presents a compelling avenue for advancing our understanding of emergent phases of matter not found in nature and unlocking new opportunities in quantum technology. Magnons, also known as spin waves, in the quantum Hall ferromagnetic state of monolayer graphene, have recently emerged as a versatile solid-state platform for designing and probing emergent phases of bosons, owing to their extraordinary tunability, long lifetime, all-electrical generation and detection scheme and their remarkable sensitivity to the magnetic environment.

However, our knowledge about the interaction between magnons and their coupling to the surrounding environments remains extremely limited. The project aims to experimentally address these key questions to facilitate future theoretical analysis and experimental development of emergent phases of magnons and a magnon-enabled spin probe. This investigation is made possible by leveraging recent advances in van der Waals assembly and moiré quantum matter, along with a creative combination of quantum electronic transport and scanning probe microscopy techniques to extract transport and thermodynamics properties of magnons in ultra-high-quality graphene heterostructures.

Ultimately, this project provides a new pathway for the design, construction, characterization, and manipulation of correlated and topological phases of bosons in solids and establishes a new, generic, and effective tool for unraveling correlated phenomena in two-dimensional materials. In addition, this project has a broader impact through research and training opportunities in quantum science for undergraduates, graduate students, and high school teachers, and a new course on two-dimensional quantum 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.