A theory of skyrmion crystal formation
| Autor: | Hu, X. C., Wu, H. T., Wang, X. R. |
|---|---|
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Nanoscale, 2022 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1039/D2NR01300B |
| Popis: | A generic theory about skyrmion crystal (SkX) formation in chiral magnetic thin films and its fascinating thermodynamic behaviours is presented. A chiral magnetic film can have many metastable states with an arbitrary skyrmion density up to a maximal value when a parameter $\kappa$, which measures the relative Dzyaloshinskii-Moriya interaction (DMI) strength, is large enough. The lowest energy state of an infinite film is a long zig-zagged ramified stripe skyrmion occupied the whole film in the absence of a magnetic field. Under an intermediate field perpendicular to the film, the lowest energy state has a finite skyrmion density. This is why a chiral magnetic film is often in a stripy state at a low field and a SkX only around an optimal field when $\kappa$ is above a critical value. The lowest energy state is still a stripy helical state no matter with or without a field when $\kappa$ is below the critical value. The multi-metastable states explains the thermodynamic path dependences of various metastable states of a film. Decrease of $\kappa$ value with the temperature explains why SkXs become metastable at low temperature in many skyrmion systems. These findings open a new avenue for SkX manipulation and skyrmion-based applications. Comment: 15 pages, 12 figures |
| Databáze: | arXiv |
| Externí odkaz: |
|