Dmitriev D V, Krivnov V Ya
Institute of Biochemical Physics of RAS, Kosygin str. 4, 119334, Moscow, Russia.
J Phys Condens Matter. 2017 Jun 1;29(21):215801. doi: 10.1088/1361-648X/aa68f6. Epub 2017 Mar 24.
We consider a spin-[Formula: see text] kagome-like chain with competing ferro- and antiferromagnetic anisotropic exchange interactions. The ground state phase diagram of this model consists of the ferromagnetic and ferrimagnetic phases. We study the ground state and the low-temperature properties on the phase boundary between these phases. The ground state on this phase boundary is macroscopically degenerate and consists of localized magnon states. We calculate the ground state degeneracy and corresponding residual entropy. The spontaneous magnetization has a jump on the phase boundary confirming the first-order type of the phase transition. In the limit of a strong anisotropy, the spectrum of the low-energy excitations has multi-scale structure governing the peculiar features of the specific heat behavior.
我们考虑一个具有竞争铁磁和反铁磁各向异性交换相互作用的自旋-[公式：见文本]类 kagome 链。该模型的基态相图由铁磁相和亚铁磁相组成。我们研究这些相之间相界处的基态和低温性质。此相界处的基态宏观简并，由局域磁振子态组成。我们计算基态简并度和相应的残余熵。自发磁化强度在相界处有跃变，证实了相变的一级类型。在强各向异性极限下，低能激发谱具有多尺度结构，决定了比热行为的独特特征。
