标题： XY型自旋二聚体在Shastry-Sutherland晶格中的量子纠缠 显示英文标题

标题： Quantum entanglement of XY-type spin dimers in Shastry-Sutherland lattice

摘要： 我们报告了对 Shastry-Sutherland 晶格中神秘无序基态起源的综合研究，BaCe$_2$ZnS$_5$在低温下的情况。磁化率和比热数据表明，直到 73 mK 仍未出现磁性有序。我们采用了一个局域自旋二聚体模型，该模型可以准确再现中子散射数据的动力学结构因子、磁化率和比热数据。值得注意的是，二聚体内交换相互作用表现出强烈的 XY 型各向异性，BaCe$_2$ZnS$_5$的基态处于纠缠态$(|\uparrow\uparrow> - |\downarrow\downarrow>)/\sqrt{2}$。这与通过海森堡相互作用获得的单重态二聚体状态形成对比。这些结果证实，BaCe$_2$ZnS$_5$处于由纠缠自旋二聚体态组成的量子顺磁态。 显示英文摘要

摘要： We report a comprehensive study on the origin of the enigmatic disordered ground state within the Shastry-Sutherland lattice, BaCe$_2$ZnS$_5$, at low temperatures. The magnetization and heat capacity data show a lack of magnetic ordering down to 73 mK. We deploy a localized spin dimer model which can accurately reproduce the dynamic structure factor of the neutron data, magnetization and heat capacity data. Remarkably, the intra-dimer exchange interaction shows strong XY-type anisotropy and the ground state of BaCe$_2$ZnS$_5$ is in an entangled state $(|\uparrow\uparrow> - |\downarrow\downarrow>)/\sqrt{2}$. This is in contrast to the singlet dimer state that is obtained for Heisenberg interactions. These results confirm that BaCe$_2$ZnS$_5$ is in a quantum paramagnet state consisting of entangled spin dimer states.