Vector chiral and multipolar orders in the spin-1/2 frustrated ferromagnetic chain in magnetic field
Vector chiral and multipolar orders in the spin-1/2 frustrated ferromagnetic chain in magnetic field
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DOI：
10.1103/physrevb.78.144404
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发表时间：
2008-10-01
影响因子：
3.7
通讯作者：
Furusaki, Akira
中科院分区：
文献类型：
--
作者：
Hikihara, Toshiya;Kecke, Lars;Furusaki, Akira
本文研究了在磁场存在下具有竞争铁磁最近邻J（1）和反铁磁次最近邻J（2）交换耦合的一维自旋1/2海森堡链。我们采用数值方法（密度矩阵重整化群方法和精确对角化方法）和有效场论方法，得到了耦合比J（1）/J（2）在较宽参数范围内的基态相图。相图内容丰富，有多种相，包括矢量手性相、双极性相和其他多极相。在矢量手征相，这出现在相对较弱的磁场中，基态表现出长程有序（LRO）的矢量手征自发打破宇称对称。在强磁场中，由于双磁振子束缚态的形成，反铁磁自旋关联的准LRO相出现。类似地，更高的多极相，如三阶（p=3）和四阶（p=4）相，通过饱和场附近的p磁振子的结合形成，显示出反铁多极自旋关联的准LRO。多极相交叉的自旋密度波相的磁场减少之前遇到的相变矢量手征相在较低的字段。我们的结果的影响准一维沮丧磁铁（例如，LiCuVO_4）。
We study the one-dimensional spin-1/2 Heisenberg chain with competing ferromagnetic nearest-neighbor J(1) and antiferromagnetic next-nearest-neighbor J(2) exchange couplings in the presence of magnetic field. We use both numerical approaches (the density-matrix renormalization-group method and exact diagonalization) and effective-field-theory approach and obtain the ground-state phase diagram for wide parameter range of the coupling ratio J(1)/J(2). The phase diagram is rich and has a variety of phases, including the vector chiral phase, the nematic phase, and other multipolar phases. In the vector chiral phase, which appears in relatively weak magnetic field, the ground state exhibits long-range order (LRO) of vector chirality which spontaneously breaks a parity symmetry. The nematic phase shows a quasi-LRO of antiferronematic spin correlation and arises as a result of formation of two-magnon bound states in high magnetic fields. Similarly, the higher multipolar phases, such as triatic (p=3) and quartic (p=4) phases, are formed through binding of p magnons near the saturation fields, showing quasi-LRO of antiferromultipolar spin correlations. The multipolar phases cross over to spin-density-wave phases as the magnetic field is decreased before encountering a phase transition to the vector chiral phase at a lower field. The implications of our results to quasi-one-dimensional frustrated magnets (e.g., LiCuVO4) are discussed.