Žukovič Milan
Institute of Physics, Faculty of Science, P. J. Šafárik University, 041 54 Košice, Slovakia.
Phys Rev E. 2019 Jun;99(6-1):062112. doi: 10.1103/PhysRevE.99.062112.
We consider the XY model with ferromagnetic (FM) and antinematic (AN) nearest-neighbor interactions on a square lattice for a varying interaction strength ratio. Besides the expected FM and AN quasi-long-range order (QLRO) phases we identify at low temperatures another peculiar canted ferromagnetic (CFM) QLRO phase, resulting from the competition between the collinear FM and noncollinear AN ordering tendencies. In the CFM phase neighboring spins that belong to different sublattices are canted by a nonuniversal (dependent on the interaction strength ratio) angle and the ordering is characterized by a fast-decaying power-law intrasublattice correlation function. Compared to the FM phase, in the CFM phase correlations are significantly diminished by the presence of zero-energy domain walls due to the inherent degeneracy caused by the AN interactions. We present the phase diagram as a function of the interaction strength ratio and discuss the character of the respective phases as well as the transitions between them.
我们考虑在正方形晶格上具有铁磁（FM）和反铁磁（AN）最近邻相互作用的XY模型，其相互作用强度比是变化的。除了在低温下我们识别出的预期铁磁和反铁磁准长程序（QLRO）相之外，由于共线铁磁和非共线反铁磁有序倾向之间的竞争，还存在另一个特殊的倾斜铁磁（CFM）QLRO相。在CFM相中，属于不同子晶格的相邻自旋以非普适（取决于相互作用强度比）角度倾斜，并且有序性由快速衰减的幂律子晶格内相关函数表征。与铁磁相相比，在CFM相中，由于反铁磁相互作用引起的固有简并性，零能量畴壁的存在显著降低了相关性。我们给出了作为相互作用强度比函数的相图，并讨论了各个相的特征以及它们之间的转变。
