自旋1三角反铁磁体中的偶极和四极自旋超固态
Dipolar and quadrupolar spin supersolid states in a spin-1 triangular antiferromagnet
浏览论文内容
中文总结 AI 辅助
采用DMRG方法研究自旋1三角反铁磁海森堡模型，识别零场、中场、高场下的偶极和四极自旋超固态，其特征可通过非弹性中子散射实验观测，结果对相关三角晶格反铁磁体有理论意义。
中文摘要 AI 辅助
我们采用密度矩阵重整化群（DMRG）方法，对处于面外磁场中的三角晶格上的自旋1反铁磁海森堡模型开展了系统的数值研究。通过绘制作为单离子各向异性$D_z$和磁场函数的量子相图，我们识别出不同的偶极和四极自旋超固态，其特征为自发U(1)对称性破缺，伴随有限自旋超流刚度与纵向平移对称性破缺共存。在零场下，具有“Y”型自旋构型的偶极自旋超固态持续存在至$D_z=0$，而四极自旋超固态则在大$D_z$区域占主导。在中场下，相图由上-上-下相主导。在低于饱和的高场下，大$D_z$区域会出现四极自旋超流，而小$D_z$区域则由具有“V”型自旋构型的偶极自旋超固态主导。我们通过对不同系统尺寸的计算，利用序参量和自旋超流刚度表征这些相。此外，我们还获取了相图范围内的动力学自旋结构因子，观测到不同相的特征谱信号，包括无能隙的戈德斯通模式和旋子型极小值，这些特征可直接通过非弹性中子散射实验观测。我们的结果为理解自旋1系统中驱动不同自旋超固态的阻挫、各向异性与塞曼相互作用之间的关联提供了理论支撑，相关结果与Na$_2$BaNi(PO$_4$)$_2$和K$_2$Ni(SeO$_3$)$_2$等多种三角晶格反铁磁体相关。
英文摘要
We present a systematic numerical study of the spin-1 antiferromagnetic Heisenberg model on the triangular lattice in an out-of-plane magnetic field, using Density Matrix Renormalization Group (DMRG) methods. By mapping out the quantum phase diagram as a function of the single-ion anisotropy $D_z$ and magnetic field, we identify distinct dipolar and quadrupolar spin supersolid states, characterized by spontaneous U(1) symmetry breaking with finite spin superfluid stiffness coexisting with longitudinal translational symmetry breaking. At zero field, the dipolar spin supersolid with a 'Y'-type spin configuration persists down to $D_z = 0$, whereas the quadrupolar spin supersolid prevails at large $D_z$. At intermediate fields, the phase diagram is dominated by an up-up-down phase. At high fields below saturation, a quadrupolar spin superfluid emerges in the large-$D_z$ regime, whereas a dipolar spin supersolid with a 'V'-type spin configuration dominates at small $D_z$. These phases are characterized through their order parameters and spin superfluid stiffness using calculations on various system sizes. Furthermore, the dynamical spin structure factor is obtained across the phase diagram, where characteristic spectral signatures of different phases are observed, including the gapless Goldstone mode and the roton-like minima. These features are directly accessible to inelastic neutron scattering experiments. Our results provide a theoretical understanding of the interplay between frustrations, anisotropy, and Zeeman interactions in driving distinct spin supersolid phases in the spin-1 system, which are relevant to various triangular-lattice antiferromagnets such as Na$_2$BaNi(PO$_4$)$_2$ and K$_2$Ni(SeO$_3$)$_2$.
发表机构
- RIKEN Center for Emergent Matter Science (CEMS)（理化学研究所物质结构研究センター）
- Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）
- RIKEN Center for Computational Science (R-CCS)（理化学研究所计算科学研究中心）
- RIKEN Center for Quantum Computing (RQC)（理化学研究所量子计算研究中心）
- RIKEN Pioneering Research Institute (PRI)（理化学研究所开创性研究所）
- Advanced Science Research Center, Japan Atomic Energy Agency（日本原子力机构先进科学研究中心）
机构由 AI 辅助整理，请以论文原文为准。
