标题： 氢氧化物双钙钛矿 CuSn(OH)$_6$中由相关质子无序引起的自旋液体模拟现象 显示英文标题

标题： Spin Liquid Mimicry in the Hydroxide Double Perovskite CuSn(OH)$_6$ Induced by Correlated Proton Disorder

摘要： 面心立方晶格由共享边的四面体组成，使其成为强挫败磁性的领先候选宿主，但相对较少的面心挫败材料已被研究。 在氢氧化物双钙钛矿 \cusnoh 中，Cu$^{2+}$ 量子自旋的磁挫败部分被强烈的詹-泰勒畸变所缓解。 然而，该系统在45 mK以下没有表现出长程磁序的迹象，而是显示出比热和磁化率中的宽泛热力学异常，表明存在短程动态自旋关联——这是量子自旋液体的典型行为。 我们提出，这种不寻常的自旋液体类似态的鲁棒性是量子自旋 $S=\frac{1}{2}$ 的量子涨落、高度畸变的面心 Cu$^{2+}$ 子晶格上的剩余挫败以及相关质子无序共同作用的结果。 类似于 YbMgGaO$_4$ 和 Herbertsmithite 中的无序诱导自旋液体模拟，质子无序通过在磁交换相互作用网络中引入随机性来破坏长程磁序。 然而，与难以控制的磁性亚晶格上的淬火替代无序不同，质子无序原则上可以通过压力驱动的质子有序转变进行调节。 这为调节磁系统中的无序程度以更好地理解其对磁基态的影响提供了前景。 显示英文摘要

摘要： The face-centered-cubic lattice is composed of edge-sharing tetrahedra, making it a leading candidate host for strongly frustrated magnetism, but relatively few face-centered frustrated materials have been investigated. In the hydroxide double perovskite \cusnoh, magnetic frustration of the Cu$^{2+}$ quantum spins is partially relieved by strong Jahn-Teller distortions. Nevertheless, the system shows no signs of long-range magnetic order down to 45\,mK and instead exhibits broad thermodynamic anomalies in specific heat and magnetization, indicating short-range dynamical spin correlations\, -- \,a behavior typical of quantum spin liquids. We propose that such an unusual robustness of the spin-liquid-like state is a combined effect of quantum fluctuations of the quantum spins $S=\frac{1}{2}$, residual frustration on the highly distorted face-centered Cu$^{2+}$ sublattice, and correlated proton disorder. Similar to the disorder-induced spin-liquid mimicry in YbMgGaO$_4$ and herbertsmithite, proton disorder destabilizes the long-range magnetic order by introducing randomness into the magnetic exchange interaction network. However, unlike the quenched substitutional disorder on the magnetic sublattice, which is difficult to control, proton disorder can in principle be tuned through pressure-driven proton ordering transitions. This opens up the prospect of tuning the degree of disorder in a magnetic system to better understand its influence on the magnetic ground state.