Unusual nature of confined modes in a chiral system: Directional transport in standing waves
Abstract
Nonreciprocity of spin-wave propagation is a well-known consequence of antisymmetric exchange contributions in magnetic spin systems that lack inversion symmetry. In this case, the energy of a state depends on the sign of its momentum as ħω (k )≠ħω (-k ) . We discuss here the consequences of this nonreciprocity on counterpropagating traveling spin-wave states. In a confined geometry we find states with well-defined nodes which are inherently phase modulated such that space-inversion symmetry of the mode profile is lost. This entails that additional spectral features become visible in ferromagnetic resonance studies of microelements with Dzyaloshinskii-Moriya interaction (DMI), allowing a quantification of the amplitude and direction of the DMI. Moreover, this interference between nonreciprocal modes forms the basis for a generalized concept of mode confinement.
- Publication:
-
Physical Review B
- Pub Date:
- June 2019
- DOI:
- 10.1103/PhysRevB.99.214429
- arXiv:
- arXiv:1609.03417
- Bibcode:
- 2019PhRvB..99u4429Z
- Keywords:
-
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Materials Science;
- 00A79;
- J.2
- E-Print:
- 26 pages, 6 figures, including supplementary