Universal 1/3 -suppression of magnonic shot noise in diffusive insulating magnets
Abstract
Extending a Boltzmann-Langevin theory to magnons, we show a universality of current-noise suppression in diffusive systems against the difference in the quantum-statistical properties of bosons and fermions. To this end, starting from a quantum kinetic equation for magnons subjected to a thermal gradient in dilute impurities, we derive a bosonic counterpart of the semiclassical Boltzmann-Langevin equation for electrons and evaluate a magnonic current noise in the diffusive insulating magnet. We theoretically discover that compared with a Poissonian shot noise of magnons in an insulating ferromagnetic junction, the magnonic shot noise is suppressed in the diffusive insulating bulk magnet and the noise-to-current ratio (Fano factor) at low temperatures exhibits a universal behavior, i.e., the same 1/3 -suppression as the one for electron transport in diffusive conductors, despite the difference in quantum-statistical properties. Finally, we show that our predictions are within experimental reach with current device and measurement technologies.
- Publication:
-
Physical Review B
- Pub Date:
- July 2019
- DOI:
- 10.1103/PhysRevB.100.014406
- arXiv:
- arXiv:1904.01151
- Bibcode:
- 2019PhRvB.100a4406N
- Keywords:
-
- Condensed Matter - Mesoscale and Nanoscale Physics;
- Condensed Matter - Materials Science;
- Condensed Matter - Quantum Gases;
- Condensed Matter - Statistical Mechanics;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 4+4 pages