标题： 在自旋-1/2 Kagome 量子自旋液体材料中识别普遍的自旋激发 显示英文标题

标题： Identifying Universal Spin Excitations in Spin-1/2 Kagome Quantum Spin Liquid Materials

摘要： 量子自旋液体（QSL）是一种奇特的物质量子态，其特征是自旋的波动，可能表现出长程纠缠。 在可能的QSL基态宿主候选材料中，$S$=1/2 kagome晶格反铁磁体尤其有希望。 通过对Zn-barlowite（Zn$_\mathrm{x}$Cu$_\mathrm{4-x}$(OD)$_\mathrm{6}$FBr,$x\simeq 0.80$）进行高分辨率非弹性中子散射测量，我们测得的自旋激发谱与QSL基态一致。 高于$\sim$1 meV 的连续散射与 herbertsmithite（Zn$_\mathrm{x}$Cu$_\mathrm{4-x}$(OD)$_6$Cl$_2$, $x\simeq 0.85$）的散射一致，另一种显著的 kagome QSL 材料，表明自旋子激发具有普遍性。 对自旋-自旋相关性的详细分析，与密度矩阵重整化群计算相比，进一步表明物理相关的哈密顿量参数下存在 QSL 基态。 测量的谱在 Zn-barlowite 中与具有间隙大小$\Delta = 1.1(2)$ meV 的有隙行为一致。 与一个简单的对相关性模型进行比较，使我们能够明确区分本征的 kagome 相关性与杂质引起的相关性。 我们的结果阐明了这一重要 QSL 候选材料家族中普遍的行为。 显示英文摘要

摘要： A quantum spin liquid (QSL) is an exotic quantum state of matter characterized by fluctuating spins which may exhibit long-range entanglement. Among the possible host candidates for a QSL ground state, the $S$=1/2 kagome lattice antiferromagnet is particularly promising. Using high resolution inelastic neutron scattering measurements on Zn-barlowite (Zn$_\mathrm{x}$Cu$_\mathrm{4-x}$(OD)$_\mathrm{6}$FBr, $x\simeq 0.80$), we measure a spin excitation spectrum consistent with a QSL ground state. Continuum scattering above $\sim$1 meV matches that of herbertsmithite (Zn$_\mathrm{x}$Cu$_\mathrm{4-x}$(OD)$_6$Cl$_2$, $x\simeq 0.85$), another prominent kagome QSL material, indicating universal spinon excitations. A detailed analysis of the spin-spin correlations, compared with density matrix renormalization group calculations, further indicate a QSL ground state for the physically relevant Hamiltonian parameters. The measured spectra in Zn-barlowite are consistent with gapped behavior with a gap size $\Delta = 1.1(2)$ meV. Comparison with a simple pair correlation model allows us to clearly distinguish intrinsic kagome correlations from impurity-induced correlations. Our results clarify the behavior that is universal within this important family of QSL candidate materials.