Transition metal
The characteristic excitation of a metal is its plasmon, which is a quantized collective oscillation of its electron density. In 1956, David Pines predicted that a distinct type of plasmon, dubbed a ‘demon’, could exist in three-dimensional (3D) metals containing more than one species of charge carrier1. Consisting of out-of-phase movement of electrons in different bands, demons are acoustic, electrically neutral and do not couple to light, so have never been detected in an equilibrium, 3D metal. Nevertheless, demons are believed to be critical for diverse phenomena including phase transitions in mixed-valence semimetals2, optical properties of metal nanoparticles3, soundarons in Weyl semimetals4and high-temperature superconductivity in, for example, metal hydrides3,5–7. Here, we present evidence for a demon in Sr2RuO4from momentum-resolved electron energy-loss spectroscopy. Formed of electrons in the
- Award ID(s):
- 2024864
- PAR ID:
- 10473530
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Nature
- Volume:
- 621
- Issue:
- 7977
- ISSN:
- 0028-0836
- Page Range / eLocation ID:
- 66 to 70
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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