Speaker
Description
A plethora of novel magnetic orders beyond the familiar ferromagnetism has recently been identified. These unusual orders arise typically from microscopic magnetic dipoles that are arranged in ways that do not result in a net magnetization. We present a systematic classification of macroscopic orders arising from microscopic-dipole configurations based on the recent standard-model description of electromagnetism and chirality in crystals [1]. Any such configuration fits into one of five categories of multipole order: parapolar (comprising, e.g., antiferromagnets that have both space- and time-inversion symmetry), electropolar (odd-parity magnets), magnetopolar (altermagnets), antimagnetopolar (eg, magnetoelectric antiferromagnets), or multipolar (coexisting electro-, magneto- and/or antimagnetopolar orders). Instead of a magnetization, unconventional magnets have a higher-rank magnetic-multipole density, or even an electric multipole density as their macroscopic order parameter. This work thus extends previous descriptions of altermagnets in terms of magnetic-octupole densities [2,3]. Characteristic electronic band-structure features can be directly linked to specific multipole densities. We propose a method for absolute quantification of the emergent macroscopic order [4].
[1] R. Winkler, U. Zülicke, PRX 16, 031039 (2026).
[2] R. Winkler, U. Zülicke, PRB 107, 155201 (2023).
[3] S. Bhowal, N. A. Spaldin, PRX 14, 011019 (2024).
[4] R. Winkler, U. Zülicke, arXiv:2509.17278 (2025).
| I am the presenting author | Yes |
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