Magnetic hopfions in solidsShow others and affiliations
2022 (English)In: APL Materials, E-ISSN 2166-532X, Vol. 10, no 11, article id 1814338Article in journal (Refereed) Published
Abstract [en]
Hopfions are an intriguing class of string-like solitons, named according to a classical topological concept classifying three-dimensional direction fields. The search for hopfions in real physical systems has been ongoing for nearly half a century, starting with the seminal work of Faddeev. However, so far, realizations in bulk solids are missing. Here, we show that hopfions appear as emergent particles of the classical Heisenberg model with competing exchange interactions. This requires going beyond the model approach used in prior work and deriving a general micromagnetic energy functional directly from a spin-lattice Hamiltonian. We present a definite parameter space in which the existence of hopfions is possible. This opens a concrete vista to combine computational approaches such as density functional theory with material informatics to find magnetic crystals that can host hopfions. As proof of principle, we show how zero-field hopfions can be visualized by the means of off-axis electron holography in a transmission electron microscope.
Place, publisher, year, edition, pages
AIP Publishing , 2022. Vol. 10, no 11, article id 1814338
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-322189DOI: 10.1063/5.0099942ISI: 000884993000001Scopus ID: 2-s2.0-85144325813OAI: oai:DiVA.org:kth-322189DiVA, id: diva2:1716162
Note
QC 20221205
2022-12-052022-12-052023-06-08Bibliographically approved