Abstract
Evolution of an overpopulated gas of magnons to a Bose-Einstein condensate and excitation of a magnon supercurrent, propelled by a phase gradient in the condensate wave function, can be observed at room temperature by means of the Brillouin light scattering spectroscopy in an yttrium iron garnet material. We study these phenomena in a wide range of external magnetic fields in order to understand their properties when externally pumped magnons are transferred towards the condensed state via two distinct channels: a multistage Kolmogorov-Zakharov cascade of the weak-wave turbulence or a one-step kinetic instability process. Our main result is that opening the kinetic instability channel leads to the formation of a much denser magnon condensate and to a stronger magnon supercurrent compared to the cascade mechanism alone.
Original language | English |
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Article number | 077203 |
Number of pages | 6 |
Journal | Physical Review Letters |
Volume | 121 |
Issue number | 7 |
DOIs | |
Publication status | Published - 15 Aug 2018 |
Bibliographical note
Financial support by the European Research Council within the Advanced Grant No. 694709 “SuperMagnonics” and by Deutsche Forschungsgemeinschaft (DFG) withinthe Transregional Collaborative Research Center SFB/TR 49 “Condensed Matter Systems with Variable Many-Body Interactions” as well as by the DFG Project No. INST 248/ 178-1 is gratefully acknowledged.
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy