Frustrated Heisenberg $J_1-J_2$ model within the stretched diamond lattice of LiYbO2
Mitchell M. Bordelon, Chunxiao Liu, Lorenzo Posthuma, Eric Kenney, M. J. Graf, N. P. Butch, Arnab Banerjee, Stuart Calder, Leon Balents, Stephen D. Wilson
We investigate the magnetic properties of LiYbO$_2$, containing a three-dimensionally frustrated, diamond-like lattice via neutron scattering, magnetization, and heat capacity measurements. The stretched diamond network of Yb$^{3+}$ ions in LiYbO$_2$ enters a long-range incommensurate, helical state with an ordering wave vector ${\bf{k}} = (0.384, \pm 0.384, 0)$ that "locks-in" to a commensurate ${\bf{k}} = (1/3, \pm 1/3, 0)$ phase under the application of a magnetic field. The spiral magnetic ground state of LiYbO$_2$ can be understood in the framework of a Heisenberg $J_1-J_2$ Hamiltonian on a stretched diamond lattice, where the propagation vector of the spiral is uniquely determined by the ratio of $J_2/|J_1|$. The pure Heisenberg model, however, fails to account for the relative phasing between the Yb moments on the two sites of the bipartite lattice, and this detail as well as the presence of an intermediate, partially disordered, magnetic state below 1 K suggests interactions beyond the classical Heisenberg description of this material.
The magnetic Ln$^{3+}$ ions in the fergusonite and scheelite crystal structures form a distorted or stretched diamond lattice which is predicted to host exotic magnetic ground states. In this study, polycrystalline samples of the fergusonite orthotantalates $M$-LnTaO$_4$ (Ln = Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er) are synthesized and then characterized using powder diffraction and bulk magnetometry and heat capacity. TbTaO$_4$ orders antiferromagnetically at 2.25 K into a commensurate magnetic cell with $\vec{k}=0$, magnetic space group 14.77 ($P2_1$$'/c$) and Tb moments parallel to the $a$-axis. No…
Quantum Paramagnet and Frustrated Quantum Criticality in a Spin-One Diamond Lattice Antiferromagnet
受金刚石晶格反铁磁体NiRh $_2$ O $_4$中拓扑量子顺磁体概念的启发，我们提出了一个描述具有自旋1局域磁矩的金刚石材料的磁相互作用和性质的极小模型.我们的模型包括第一和第二邻居海森堡相互作用，以及一个本地的单离子自旋各向异性，这是允许的自旋一性质的本地矩和四重对称的系统。我们指出，存在着从单离子自旋各向异性占优势时的平凡量子顺磁体到交换占优势时的磁有序态的量子相变。由于受抑自旋相互作用，在量子顺磁态的磁激发支持广泛的简并带谱中的最低点。当系统接近转变时，广泛简并的玻色子模式在临界点变得至关重要，从而产生不寻常的磁性。我们的相图和实验预测的不同阶段提供了一个指南针的识别的基态NiRh $_2$ O $_4$。虽然我们的结果与拓扑量子顺磁的提议有本质的不同，但它代表了自旋为1的金刚石晶格反铁磁体的有趣的可能性。
Magnetism and spin dynamics of Na$_5$Yb(MoO$_4$)$_4$: A weakly interacting rare-earth stretched diamond lattice
National Taiwan University（国立台湾大学）；Academia Sinica（中央研究院）；Sungkyunkwan University（成均馆大学）；KEK（高能加速器研究机构）；National Tsing Hua University（国立清华大学）；National Synchrotron Radiation Research Center（国家同步辐射研究中心）；University of Johannesburg（约翰内斯堡大学）
The $A$-site spinel NiRh$_2$O$_4$ is the only known realization of a spin-1 diamond lattice magnet and is predicted to host unconventional magnetic phenomena driven by frustrated nearest and next-nearest neighbor exchange as well as orbital degeneracy. Previous works found no sign of magnetic order but found a gapped dispersive magnetic excitation indicating a possible valence bond magnetic ground state. However, the presence of many competing low energy degrees of freedom and limited empirical microscopic constraints complicates further analysis. Here, we carry out resonant inelastic x-ray sc…
Quantum order by disorder in frustrated diamond lattice antiferromagnets
本文提出了一个受抑金刚石晶格反铁磁体的量子理论。考虑到量子涨落作为缓解自旋阻挫的主要机制，我们发现了一个丰富的相图，除了Néel相外，还包括六个具有共面螺旋有序的相。通过计算这些有序相的比热，我们得到了$(k,k,0)$ -螺旋有序与实验比热数据之间的显着协议的金刚石晶格尖晶石化合物MnSc $_2$ S $_4$，Co $_3$ O $_4$和CoRh $_2$ O $_4$，即比热数据是一个强有力的证据$(k,k,0)$ -螺旋有序在所有这些材料.这一预测可以在未来的中子散射实验中进行测试Co $_3$ O $_4$和CoRh $_2$ O $_4$，并与现有的中子散射数据MnSc $_2$ S $_4$是一致的。基于这一协议，我们推断挫折和量子涨落的强度之间的单调增加的关系。
We report the discovery of a spin one diamond lattice in NiRh2O4. This spinel undergoes a cubic to tetragonal phase transition at T = 440 K that leaves all nearest neighbor interactions equivalent. In the tetragonal phase, magnetization measurements show a Ni2+ effective moment of p(eff) = 3.3(1) and dominant antiferromagnetic interactions with Θ(CW) = -11.3(7) K. No phase transition to a long-range magnetically ordered state is observed by specific heat measurements down to T = 0.1 K. Inelastic neutron scattering measurements on sub-stoichiometric NiRh2O4 reveal possible valence-bond behavior…
Nonconventional magnetic order in frustrated diamond lattice antiferromagnet CoAl2O4 studied by neutron diffraction and classical Monte-Carlo simulation
已知在金刚石A晶格上具有磁性Co2+离子的CoAl 2 O 4尖晶石是磁性受抑的。我们比较了在零磁场和外加磁场中测量的中子单晶衍射图与经典蒙特卡罗模型得到的衍射图。在模拟中，我们测试各种参数对衍射图案的影响：最近的，J1，和下一个最近的，J2，邻居的相互作用，磁场施加沿主要结晶方向的比率，和随机无序的A（Co 2+）和B（Al 3+）的网站。我们的结论是，到目前为止所考虑的模型解释了磁布拉格峰的加宽在零磁场和它们的各向异性响应施加磁场只有部分。由于我们的单晶体的整体性能是各向同性的，我们认为，它的微观结构，特别是<111>-孪晶界，可能是CoAl 2 O 4的非常规磁秩序的原因。
We report the magnetic properties of $A$-site spinel compound MnSc$_2$Se$_4$. The macroscopic magnetic measurements uncovers successive magnetic transitions at $T_{\rm{N1}}$= 2.04 K, followed by two further transitions at $T_{\rm{N2}}$=1.8 K and $T_{\rm{N3}}$=1.6 K. Neutron powder diffraction reveals that both, $T_{\rm{N2}} < T < T_{\rm{N1}}$ and $T <T_{\rm{N3}}$, orders are associated with the propagation vector $k$=(3/4 3/4 0), while the magnetic structures are collinear amplitude modulated and helical, respectively. Using neutron powder spectroscopy we demonstrated the effect of substitutio…
Motivated by the recent synthesis of the spin-1 A-site spinel NiRh$_{\text 2}$O$_{\text 4}$, we investigate the classical to quantum crossover of a frustrated $J_1$-$J_2$ Heisenberg model on the diamond lattice upon varying the spin length $S$. Applying a recently developed pseudospin functional renormalization group (pf-FRG) approach for arbitrary spin-$S$ magnets, we find that systems with $S \geq 3/2$ reside in the classical regime where the low-temperature physics is dominated by the formation of coplanar spirals and a thermal (order-by-disorder) transition. For smaller local moments $S$=1…
The frustrated quantum spin system on the distorted diamond chain lattice suitable for the alumoklyuchevskite is investigated using the numerical diagonalization of finite-size clusters and the level spectroscopy analysis. It is found that this model exhibits three quantum phases; the ferrimagnetic phase, the spin gap one, and the gapless Tomonaga-Luttinger liquid depending on the exchange coupling parameters. The ground state phase diagram is presented.
We report the physical properties of Tb2Hf2O7 based on ac magnetic susceptibility χ_ac(T), dc magnetic susceptibility χ(T), isothermal magnetization M(H), and heat capacity C_p(T) measurements combined with muon spin relaxation (\muSR) and neutron powder diffraction measurements. No evidence for long-range magnetic order is found down to 0.1 K. However, χ_ac(T) data present a frequency-dependent broad peak (near 0.9 K at 16 Hz) indicating slow spin dynamics. The slow spin dynamics is further evidenced from the \muSR data (characterized by a stretched exponential behavior) which show persistent…
Three-dimensionally (3D) frustrated magnets generally exist in the magnetic diamond and pyrochlore lattices, in which quantum fluctuations suppress magnetic orders and generate highly entangled ground states (GS). LiYbSe2 in a previously unreported pyrochlore lattice was discovered from LiCl flux growth. Distinct from the quantum spin liquid (QSL) candidate NaYbSe2 hosting a perfect triangular lattice of Yb3+, LiYbSe2 crystallizes in the cubic pyrochlore structure with space group Fd-3m (No. 227). The Yb3+ ions in LiYbSe2 are arranged on a network of corner-sharing tetrahedra, which is particu…
Spin order and dynamics in the diamond-lattice Heisenberg antiferromagnets CuRh2O4 and CoRh2O4
金刚石晶格上的反铁磁绝缘体是具有奇异磁现象的候选材料，从自旋轨道纠缠到简并螺旋基态和拓扑顺磁性。相对于其他三维磁性离子网络，如几何阻挫烧绿石晶格，金刚石晶格磁性在实际材料中的研究还不成熟。在这项工作中，我们通过热磁和中子散射测量来表征模型A位尖晶石CoRh 2 O 4（钴蔷薇辉石）和CuRh 2 O 4（铜蔷薇辉石）的磁性，并进行群论分析，Rietveld精化，平均场论和自旋波理论计算来分析实验结果。我们的研究表明，立方CoRh_2 O_4是一个典型的S=3/2金刚石晶格Heisenberg反铁磁体，最近邻交换J = 0.63meV，在25 K以下为Neel有序基态。在四边形扭曲CuRh 2 O 4中，第三近邻自旋之间的竞争交换相互作用导致在24 K下出现无公度自旋螺旋，其磁传播矢量k =（0，0，0.79）.强减少的有序矩观察到的S=1/2自旋CuRh 2 O 4和捕获我们的1/S校正交错磁化。我们的工作确定CoRh 2 O 4和CuRh 2 O 4作为参考材料，以指导未来的工作寻找奇异的量子行为在金刚石晶格反铁磁体。
The ground state of a molecular diamond-lattice compound (ET)Ag$_4$(CN)$_5$ is investigated by the magnetization and nuclear magnetic resonance spectroscopy. We found that the system exhibits antiferromagnetic long-range ordering with weak ferromagnetism at a high temperature of 102 K owing to the strong electron correlation. The spin susceptibility is well fitted into the diamond-lattice Heisenberg model with a nearest neighbor exchange coupling of 230 K, indicating the less frustrated interactions. The transition temperature elevates up to $\sim$195 K by applying pressure of 2 GPa, which rec…
We investigate the crystal structure, magnetic properties, and crystalline-electric field of tetragonal, $I4_1/amd$, NaCeO$_2$. In this compound, Ce$^{3+}$ ions form a tetragonally elongated diamond lattice coupled by antiferromagnetic interactions ($Θ_{CW} = -7.69$ K) that magnetically order below $T_N = 3.18$ K. The Ce$^{3+}$ $J = 5/2$ crystalline-electric field-split multiplet is studied via inelastic neutron scattering to parameterize a $J_{eff} = 1/2$ ground state doublet comprised of states possessing mixed $|m_z \rangle$ character. Neutron powder diffraction data reveal the onset of $A$…
The spin-1/2 Heisenberg antiferromagnet on the frustrated diamond-decorated square lattice is known to feature various zero-field ground-state phases, consisting of extended monomer-dimer and dimer-tetramer ground states as well as a ferrimagnetic regime. Using a combination of analytical arguments, density matrix renormalization group (DMRG), exact diagonalization, as well as sign-problem-free quantum Monte Carlo (QMC) calculations, we investigate the properties of this system and the related Lieb lattice in the presence of a finite magnetic field, addressing both the ground-state phase diagr…
Spin-1/2 Heisenberg diamond-like decorated honeycomb lattice in a magnetic field from the perspective of localized magnons and exact diagonalization
Faculty of Science, P. J. Šafárik University（帕·约·沙法里克大学理学院）；Laboratoire de Physique Théorique et Modélisation, CNRS UMR 8089, CY Cergy Paris Université（CY塞尔吉巴黎大学，CNRS UMR 8089理论物理与建模实验室）
Approaching the Ground State of Frustrated A-site Spinels: A Combined Magnetization and Polarized Neutron Scattering Study
我们重新研究磁阻挫，{ \it金刚石晶格反铁磁体}尖晶石FeAl $_2$ O $_4$和MnAl $_2$ O $_4$使用磁化测量和极化中子的漫散射。在FeAl $_2$ O $_4$中，宏观测量证实了在13 K附近零场冷却磁化率的“尖点”。动态磁化率和{ \it记忆效应}实验提供的结果不符合该材料中的典型自旋玻璃情形。通过极化中子散射研究，证实了FeAl $_2$ O $_4$在低至4~K的温度范围内不存在长程磁序。通过模拟粉末平均微分磁中子散射截面，我们估计，在这种化合物中的自旋-自旋相关延伸到第三个最近邻壳。Landé $g$因子的估计值指向Fe $^{2+}$的轨道贡献。这也得到了居里-外斯磁化率分析的支持。而MnAl $_2$ O $_4$在低于$\approx$ 40~K时发生磁相变，进入长程有序态，这一点得到了宏观测量和极化中子衍射的证实。然而，极化中子研究揭示了显著的自旋涨落与长程反铁磁有序共存的存在。磁扩散强度表明与FeAl $_2$ O $_4$类似的短程有序。本工作的结果支持自旋自旋相关性的重要性，在理解磁响应的挫折磁铁一样，$A$网站尖晶石具有主导的短程自旋相关性，让人想起“自旋液体”状态。
Approaching Kasteleyn transition in frustrated quantum Heisenberg antiferromagnets
CY Cergy Paris Université（塞吉-蓬图瓦兹大学）；P. J. Šafárik University（帕维尔·约瑟夫·沙法里克大学）；Ecole Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院）；Yukhnovskii Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine（乌克兰国家科学院尤赫诺夫斯基凝聚态物理研究所）；Ivan Franko National University of Lviv（利沃夫伊万·弗兰科大学）；École Normale Supérieure – Université PSL（巴黎高等师范学院-巴黎文理研究大学）；Sorbonne Université（索邦大学）；Collége de France（法兰西公学院）；RWTH Aachen University（亚琛工业大学）
The stretched diamond lattice material LiYbO2 has recently been reported to exhibit two magnetic transitions ($T_{N1} = 1.1 K$, $T_{N2} = 0.45 K$) via specific heat, magnetization, and neutron scattering measurements [Bordelon et al., Phys. Rev. B 103, 014420 (2021)]. Here we report complementary magnetic measurements down to T = 0.28 K via the local probe technique of muon spin relaxation. While we observe a rapid increase in the zero-field muon depolarization rate at $T_{N1}$, we do not observe any spontaneous muon precession for $T < T_{N1}$, which is typically associated with long-range ma…
