Thermodynamically stable skyrmion lattice in tetragonal frustrated antiferromagnet with dipolar interaction
| Autor: | O. I. Utesov |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Physics
Condensed Matter - Materials Science Condensed matter physics Strongly Correlated Electrons (cond-mat.str-el) Skyrmion Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Brillouin zone Condensed Matter - Strongly Correlated Electrons Tetragonal crystal system Reciprocal lattice 0103 physical sciences Antiferromagnetism 010306 general physics 0210 nano-technology Anisotropy Topological quantum number Phase diagram |
| DOI: | 10.48550/arxiv.2012.08422 |
| Popis: | Motivated by recent experimental results on GdRu$_2$Si$_2$ [Khanh, N.D., Nakajima, T., Yu, X. et al., \emph{Nat. Nanotechnol.} \textbf{15}, 444-449 (2020)], where nanometric square skyrmion lattice was observed, we propose simple analytical mean-field description of the high-temperature part of the phase diagram of centrosymmetric tetragonal frustrated antiferromagnets with dipolar interaction in the external magnetic field. In the reciprocal space dipolar forces provide momentum dependent biaxial anisotropy. It is shown that in tetragonal lattice in the large part of the Brillouin zone for mutually perpendicular modulation vectors in the $ab$ plane this anisotropy has mutually perpendicular easy axes and collinear middle axes, what leads to double-Q modulated spin structure stabilization. The latter turns out to be a square skyrmion lattice in the large part of its stability region with the topological charge $\pm 1$ per magnetic unit cell, which is determined by the frustrated exchange coupling, and, thus, nanometer-sized. In the presence of additional single-ion easy-axis anisotropy, easy and middle axes can be swapped, which leads to different phase diagram. It is argued that the latter case is relevant to GdRu$_2$Si$_2$. Comment: 11 pages, 5 figures |
| Databáze: | OpenAIRE |
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