AI 中文总结
本文建立含单一自由参数的理论模型，解释赫伯茨mithite中由QSL自旋子介导的见证自旋玻璃现象，匹配多类实验数据，预测Z₂与U(1)型QSL的中子散射差异及高浓度下的相变，为区分QSL类型提供测试方法。
AI 中文摘要
赫伯茨mithite是典型的量子自旋液体（QSL）候选材料，被认为具有长程纠缠基态和退禁闭的分数化自旋子激发。磁杂质（替代非磁性Zn²⁺位点的自旋-1/2 Cu²⁺自旋）的存在阻碍了这些性质的确认。最近，这些杂质被重新概念化为QSL的“见证者”，继承由QSL自旋子介导的长程相互作用和纠缠，导致见证者在260 mK以下形成自旋玻璃。本文对这一想法给出完整理论解释。尽管仅含一个自由参数（见证者- kagome自旋耦合），我们的模型仍能捕捉全部实验数据，包括：见证者中自旋玻璃的形成、磁噪声的频率和温度依赖性、直流磁化率随温度变化的尖锐峰，以及2 K下的静态中子散射结构因子。Z₂和U(1)两类QSL候选均与所有数据有相似吻合，但我们的模型预测Z₂与U(1)在260 mK以下的中子散射强度存在定性差异，提供了长期寻求的区分二者的决定性测试。我们还预测了温度和见证者浓度依赖的相图，发现高浓度下Z₂和U(1)会向不同的长程有序见证者态发生相变。
英文摘要
Herbertsmithite is a prototypical candidate quantum spin liquid (QSL), believed to feature a long-range entangled ground state and deconfined fractionalised spinon excitations. Confirmation of these properties has been hindered by the presence of magnetic impurities (spin-1/2 Cu2+ spins substituted onto non-magnetic Zn2+ sites). Recently these impurities were reconceptualised as 'witnesses' of the QSL, inheriting long-range interactions and entanglement mediated by the QSL spinons, leading to spin glass formation amongst witnesses below 260 mK. Here we present a full theoretical account of this idea. Despite having only one free parameter (the witness-kagome spin coupling), our model captures the full range of experimental data, including: the formation of a spin glass amongst witnesses; the frequency and temperature dependence of the magnetic noise; a sharp peak in the DC magnetic susceptibility as a function of temperature; and the static neutron scattering structure factor at 2 K. Both candidate QSLs (Z2 and U(1)) give similar agreement with all data; however, our model predicts a qualitative difference between the Z2 and U(1) neutron scattering intensities below 260 mK, providing a long-sought definitive test to distinguish the two cases. We also predict phase diagrams as a function of temperature and witness concentration, finding a phase transition to different long-range ordered witness states for Z2 and U(1) at high concentration.
Comments20 pages, 18 figures
