Inertial spin waves in spin spirals

Physical review. B./Physical review. B, vol. 109

Abstract

Inertial effects in spin dynamics emerge on picosecond timescales, giving rise to nutational excitations at THz frequencies. Here, we describe a general framework for investigating the precessional and nutational excitations in any type of spin structure within linear spin-wave theory. We consider the particular cases of planar and conical spin spirals in detail. We observe a change in the sign of the curvature of the high-frequency nutational spin-wave band as the spiral period is decreased when passing from the ferromagnetic to the antiferromagnetic limit. We identify conditions for the interaction parameters where the curvature changes sign and asymptotical flat bands are formed.

Authors 3

1. Mikhail A. Cherkasskii corresponding Aachen Institute for Theoretical Solid State Physics

   RWTH Aachen University

   Affiliation as printed

   Institute for Theoretical Solid State Physics

   Institute for Theoretical Solid State Physics, RWTH Aachen University, DE-52074 Aachen, Germany

2. Ritwik Mondal

   Indian Institute of Technology Dhanbad

   Affiliation as printed

   Indian Institute of Technology (ISM) Dhanbad

   Department of Physics, Indian Institute of Technology (ISM) Dhanbad, IN-826004 Dhanbad, India

3. Levente Rózsa

   Budapest University of Technology and Economics · HUN-REN Wigner Research Centre for Physics · Institute for Solid State Physics and Optics

   Affiliation as printed

   Budapest University of Technology and Economics

   Institute of Solid State Physics and Optics

   Department of Theoretical Physics, Budapest University of Technology and Economics, H-1111 Budapest, Hungary

   Department of Theoretical Solid State Physics, Institute of Solid State Physics and Optics, HUN-REN Wigner Research Centre for Physics, H-1525 Budapest, Hungary