Batle Josep
Departament de Física, Universitat de les Illes Balears, 07122, Palma de Mallorca, Balearic Islands, Spain.
Sci Rep. 2021 Feb 18;11(1):4154. doi: 10.1038/s41598-021-83359-x.
The interplay between the special triangular/hexagonal two dimensional lattice and the long range dipole-dipole interaction gives rise to topological defects, specifically the vortex, formed by a particular arrangement of the interacting classic dipoles. The nature of such vortices has been traditionally explained on the basis of numerical evidence. Here we propose the emerging formation of vortices as the natural minimum energy configuration of interacting (in-plane) two-dimensional dipoles based on the mechanism of spontaneous symmetry breaking. As opposed to the quantal case, where spin textures such as skyrmions or bimerons occur due to non-linearities in their Hamiltonian, it is still possible to witness classic topological structures due only to the nature of the dipole-dipole force. We shall present other (new) topological structures for the in-plane honeycomb lattice, as well as for two-dimensional out-of-plane dipoles. These structures will prove to be essential in the minimum energy configurations for three-dimensional simple hexagonal and hexagonal-closed-packed structures, whose energies in the bulk are obtained for the first time.
特殊的三角形/六边形二维晶格与长程偶极-偶极相互作用之间的相互作用会产生拓扑缺陷，特别是由相互作用的经典偶极子的特定排列形成的涡旋。传统上，这种涡旋的性质是根据数值证据来解释的。在此，我们基于自发对称性破缺机制，提出涡旋的出现是相互作用的（面内）二维偶极子的自然最低能量构型。与量子情况不同，在量子情况下，诸如斯格明子或双聚子等自旋纹理是由于其哈密顿量中的非线性而出现的，而仅由于偶极-偶极力的性质，仍然有可能见证经典拓扑结构。我们将展示面内蜂窝晶格以及二维面外偶极子的其他（新的）拓扑结构。这些结构对于三维简单六边形和六方密堆积结构的最低能量构型至关重要，其体能量首次得以获得。
