AI 中文总结
该研究针对含交替铁磁与反铁磁自旋-1/2链的二维量子反铁磁系统，揭示了磁场驱动其维度降低的机制，为水氯铜矿的非弹性中子散射提供了可观测特征。
AI 中文摘要
低维度会增强量子涨落，进而引发新型量子物态的出现。在实际材料中，低维度通常源于空间上强各向异性的耦合。本文展示了一种不同的机制：在具有交替铁磁（FM）和反铁磁（AFM）自旋-1/2链耦合的二维系统中，外加磁场可驱动维度降低。在磁场作用下，铁磁链发生极化并变硬，抑制了反铁磁横向涨落在链间的传播，从而在低能下有效诱导出一维行为。针对描述水氯铜矿（Cu₂(OH)₃Br）的模型，量子蒙特卡罗动力学计算表明，超过临界磁场后，低能谱会变为一维反铁磁海森堡自旋-1/2链的低能谱，呈现出与磁场相关的非共线两自旋子涨落，为非弹性中子散射提供了清晰的特征信号。
英文摘要
Low dimensionality enhances quantum fluctuations, triggering novel states of quantum matter to emerge. In real materials, low dimensionality usually arises from spatially strongly anisotropic couplings. Here, we demonstrate a different mechanism: in two-dimensional systems with coupled alternating ferromagnetic (FM) and antiferromagnetic (AFM) spin-$1/2$ chains, an applied magnetic field may drive a dimensional reduction. Under magnetic field, the FM chains polarize and stiffen, suppressing the propagation of transverse AFM fluctuations from one chain to another, and effectively induce one-dimensional behavior at low energies. For a model describing botallackite, Cu$_2$(OH)$_3$Br, quantum Monte Carlo dynamics show that beyond a critical magnetic field, the low-energy spectrum reduces to that of a one-dimensional AFM Heisenberg spin-$1/2$ chain with field-dependent incommensurate two-spinon fluctuations, providing clear signatures for inelastic neutron scattering.
CommentsMain text: 8 pages including the end matter and 6 figures. Supplemental material: 6 pages
