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MA: Fachverband Magnetismus
MA 8: Altermagnets II
MA 8.2: Vortrag
Montag, 9. März 2026, 15:15–15:30, HSZ/0002
Pines' Demons in d-Wave Altermagnets: From Hidden Modes to Fano-Demon States — •Habib Rostami1 and Johannes Hofmann2 — 1Department of Physics, University of Bath, United Kingdom — 2Department of Physics, Gothenburg University, Sweden
We develop a Fermi-liquid description of d-wave altermagnets and analyze their charge and spin collective excitations [1]. In addition to the conventional undamped plasmon, where both spin components oscillate in phase, we find an acoustic plasmon (demon) mode with out-of-phase spin dynamics. Using the dynamical structure factor, we show that the demon frequency and spectral weight depend sensitively on the Landau parameters and on the propagation direction. As a function of angle, the acoustic mode evolves from a hidden state with vanishing spectral weight in the density response, to a weakly damped propagating demon, and, below a critical interaction parameter, to a Fano-demon mixed state that strongly hybridizes with particle-hole excitations and exhibits an asymmetric line shape. We briefly discuss possible implications for probing and exploiting collective electron spin oscillations in altermagnetic materials.
[1] H. Rostami and J. Hofmann, Fermi liquid theory of d-wave altermagnets: demon modes and Fano-demon states, arXiv:2505.07083, to appear in Physical Review Letters.
Keywords: d-wave altermagnet; Plasmon mode; Pines’ demon mode