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MA: Fachverband Magnetismus
MA 48: Magnonics II
MA 48.6: Vortrag
Donnerstag, 12. März 2026, 16:15–16:30, HSZ/0004
Antiferromagnetic magnon condensation — •David Angster1, Tobias Dannegger1, Ulrich Nowak1, and Verena Brehm2 — 1University of Konstanz, Germany — 2Eindhoven University of Technology, Netherlands
The Bose-Einstein condensation (BEC) is a phase transition of a boson gas in which the ground state becomes macroscopically occupied below a critical temperature. BEC of bosonic quasiparticles, such as magnons, has been realised experimentally through active pumping of their density above a threshold value, since their number is not conserved in thermal equilibrium. This non-equilibrium magnon BEC was first demonstrated by Demokritov et al. [1]. Here, we present atomistic spin dynamics (ASD) simulations of antiferromagnetic hematite. The pumping of high-energy magnon modes triggers magnon redistribution via scattering processes that ultimately lead to condensation in the ground state, visible as an overproportional and non-thermal occupation of the low-frequency modes. Exploiting the non-linearity of ASD, we explore the key characteristics of BEC formation [2]: 1. a pumping threshold, 2. the spontaneous emergence of coherence, and 3. the shift of the magnon chemical potential.
[1] Demokritov et al., Nature 443, 430-433 (2006)
[2] Schneider et al., Nat. Nanotechnol. 15, 457-461 (2020)
Keywords: Bose-Einstein condensation; nonlinear dynamics; atomistic spin dynamics; antiferromagnetism; phase transitions