CAREER: Magnetic topological phases in dissipative systems

Boston College, Chestnut Hill MA

Investigators

Abstract

This award is funded in part under the American Rescue Plan Act of 2021 (Public Law 117-2). NONTECHNICAL SUMMARY This CAREER award supports theoretical research and education to advance the fundamental understanding of topological phases in magnetic materials. Topology is a branch of mathematics that addresses properties that cannot be altered by distorting a system. The application of topology to condensed matter systems has led to the discovery of many new phenomena and topological materials, for example topological insulators. The bulk of these materials are insulators, and so, do not conduct electricity. However, they are conducting on their surfaces and corners. Topology requires that these "edge states" are present no matter how disordered the material might be. While past research efforts have been focused on topological phases in which the system’s energy is conserved, recent years have witnessed a burst of research on systems where, owing to significant interactions with the environment, energy may be gained or lost. The PI aims to expand this newly established theoretical framework to address the topological properties of magnetic systems. Topological magnetic materials have been proposed as building blocks for numerous technological applications and might serve as solid-state platforms for observing novel dissipative topological phenomena. However, harnessing their potential requires a better understanding of the interplay between their topology and their ubiquitous dissipative interactions with the surrounding crystalline environment. The PI will explore realistic potential platforms of dissipative topological magnetic phenomena and will develop new theoretical techniques to provide predictions that can guide current and future experimental explorations. In addition to mentoring and training graduate and undergraduate students participating in this research, the PI plans to develop a pedagogical course on the recent developments in the field of spintronics. As co-founder of the Women in Physics Society at Boston College, the PI will continue to create new networking opportunities for undergraduate and graduate women. Furthermore, the PI aims to develop a workshop for junior researchers from underdeveloped countries. TECHNICAL SUMMARY This CAREER award supports theoretical research and education to advance the fundamental understanding of magnetic topological phases in dissipative systems. This project is aimed to investigate magnetic topological phases within the framework of non-Hermitian topological theories and to explore spin-independent mechanisms for the generation of topologically nontrivial magnon bands. Specifically, the project consists of three closely related research efforts: 1) investigating the fundamental properties of topologically-protected non-Hermitian magnon edge states and exploring experimentally feasible platforms to realize and probe topological magnon transport unhindered by nonlinear spin bulk dynamics; 2) identifying the essential ingredients for the breakdown of the bulk-edge correspondence in magnetic systems and developing new analytical techniques to predict experimental observables of the magnetic skin effect; 3) exploring the emergence and the transport properties of topologically-protected non-Hermitian magnon-polaron edge states in ionic crystals. In addition to mentoring and training graduate and undergraduate students participating in this research, the PI plans to develop a pedagogical course at the graduate level on the recent developments in the field of spintronics. As co-founder of the Women in Physics Society at Boston College, the PI will continue to create new networking opportunities for undergraduate and graduate women. Furthermore, the PI aims to develop a workshop for junior researchers from underdeveloped countries. 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.