TY  - JOUR
AU  - Grytsiuk, Sergii
AU  - Blügel, S.
TI  - Micromagnetic description of twisted spin spirals in the B20 chiral magnet FeGe from first principles
JO  - Physical review / B
VL  - 104
IS  - 6
SN  - 2469-9969
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2021-03220
SP  - 064420
PY  - 2021
AB  - Using the model of classical Heisenberg exchange and Dzyaloshinskii-Moriya (DM) interaction, we show that the ground state of the B20 FeGe chiral magnet is a superposition of twisted helical spin-density waves formed by different sublattices of the crystal. Such twisted spin-density waves propagate in the same direction but with different phases and different directions of the rotation axes. We derive an advanced micromagnetic expression describing the exchange and DM interaction for such magnetic structures. In particular, we show that such magnetic order gives rise to new contributions to the micromagnetic energies of the exchange and DM interactions. By employing first-principles calculations based on density functional theory and using our micromagnetic model we show that the magnitude of the spin-spiral twist in B20 FeGe is of the same order as global spiraling. While the energy difference between the ground state of twisted spirals and the ferromagnetic state is in good agreement with the experimental results, for the spin spirals without a twist it is smaller by a factor of 3. In addition, we verify our results by employing spin-dynamics simulations. This calls for new experiments exploring the ground state properties of B20 chiral magnets.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000684129900001
DO  - DOI:10.1103/PhysRevB.104.064420
UR  - https://juser.fz-juelich.de/record/894438
ER  -