Abstract
Dynamics in a quantum material is described by quantized collective motion: a quasiparticle. The single-quasiparticle description is useful for a basic understanding of the system, whereas a phenomenon beyond the simple description such as quasiparticle decay which affects the current carried by the quasiparticle is an intriguing topic. The instability of the quasiparticle is phenomenologically determined by the magnitude of the repulsive interaction between a single quasiparticle and the two-quasiparticle continuum. Although the phenomenon has been studied in several materials, thermodynamic tuning of the quasiparticle decay in a single material has not yet been investigated. Here we show, by using neutron scattering, magnetic field control of the magnon decay in a quantum antiferromagnet RbFeCl3, where the interaction between the magnon and continuum is tuned by the field. At low fields where the interaction is small, the single magnon decay process is observed. In contrast, at high fields where the interaction exceeds a critical magnitude, the magnon is pushed downwards in energy and its lifetime increases. Our study demonstrates that field control of quasiparticle decay is possible in the system where the two-quasiparticle continuum covers wide momentum-energy space, and the phenomenon of the magnon avoiding decay is ubiquitous.
| Original language | English |
|---|---|
| Article number | 125 |
| Journal | Nature Communications |
| Volume | 15 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2024 |
Funding
Prof. M. Matsumoto and Dr. R. Verresen are greatly appreciated for fruitful discussions. We are grateful to R. Ishii and H. Tanaka for the advice on growing single crystals and D. Kawana, T. Asami, R. Sugiura, and M. K. Graves-Brook for supporting us in the neutron scattering experiment at HRC and HYSPEC. The neutron experiment at the Materials and Life Science Experimental Facility of the J-PARC was performed using a user program (Proposal No. 2018S01). The neutron experiment at JRR-3 was performed using a user program (Proposal No. 21403). A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Travel expenses for the neutron scattering experiments performed using HYSPEC at ORNL, USA, were supported by the US-Japan Cooperative Research Program on Neutron Scattering. S. Hasegawa was supported by the Japan Society for the Promotion of Science through the Leading Graduate Schools (MERIT). This project was supported by JSPS KAKENHI Grant Nos. 19KK0069, 20K20896, and 21H04441. Prof. M. Matsumoto and Dr. R. Verresen are greatly appreciated for fruitful discussions. We are grateful to R. Ishii and H. Tanaka for the advice on growing single crystals and D. Kawana, T. Asami, R. Sugiura, and M. K. Graves-Brook for supporting us in the neutron scattering experiment at HRC and HYSPEC. The neutron experiment at the Materials and Life Science Experimental Facility of the J-PARC was performed using a user program (Proposal No. 2018S01). The neutron experiment at JRR-3 was performed using a user program (Proposal No. 21403). A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Travel expenses for the neutron scattering experiments performed using HYSPEC at ORNL, USA, were supported by the US-Japan Cooperative Research Program on Neutron Scattering. S. Hasegawa was supported by the Japan Society for the Promotion of Science through the Leading Graduate Schools (MERIT). This project was supported by JSPS KAKENHI Grant Nos. 19KK0069, 20K20896, and 21H04441.