2020/12/15 by Oleg I. Utesov · 1 citation
Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Dipole #Frustration #Lattice (music) #Magnetic properties of thin films #Materials science #Phase (matter) #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Skyrmion #Tetragonal crystal system #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.103.064414
published as Phys. Rev. B 103, 064414 (2021) · 11 pages, 5 figures
arxiv created 2020/12/15 · openalex created_date 2020/12/21 · openalex publication_date 2021/02/08 · arxiv updated 2021/02/17 · openalex updated_date 2026/08/05
Motivated by recent experimental results for GdRu2Si2 [Khanh et al., Nat. Nanotechnol. 15, 444 (2020)], in which a nanometric square skyrmion lattice was observed, we propose a 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. Dipolar forces provide momentum-dependent biaxial anisotropy in reciprocal space. It is shown that in a 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, which leads to double-Q modulated spin structure stabilization. In the large part of its stability region, the latter turns out to be a square skyrmion lattice with a topological charge of \ifmmode±\else\textpm\fi1 per magnetic unit cell, which is determined by the frustrated exchange coupling and thus nanometer sized. Easy and middle axes can be swapped in the presence of additional single-ion easy-axis anisotropy. This results in the different phase diagram. It is argued that the latter case is relevant to GdRu2Si2.