量子自旋液体(QSL)是一种奇异的物质状态,受到广泛的研究。然而,泛在无序与量子SL行为之间的关系尚不清楚。在这里,通过对两个kagomé晶格QSL候选物Tm $_3$ Sb $_3$ Zn $_2$ O $_{14}$和Tm $_3$ Sb $_3$ Mg $_2$ O $_{14}$进行比较实验研究,这两个候选物彼此同构,但分别具有强和弱的结构无序,我们明确地表明,无序可以诱导类似自旋液体的特征。特别是,两种化合物都显示出主要的反铁磁相互作用,Tm $_3$ Sb $_3$ Zn $_2$ O $_{14}$和Tm $_3$ Sb $_3$ Mg $_2$ O $_{14}$的居里-外斯温度分别为-17.4和-28.7 K,但在低至约0.05 K时仍保持无序。比热的结果表明,存在的无间隙的磁激励,其特征在于由一个剩余的线性项。用非弹性中子散射(INS)方法得到的低温磁激发谱具有宽的连续谱。所有这些观察结果都与QSL的观察结果一致。然而,我们发现,在Tm $_3$ Sb $_3$ Zn $_2$ O $_{14}$,它具有很强的无序从随机混合的磁性Tm $^{3+}$和Zn-Zn $^{2+}$,在比热和INS测量中观察到的低能量磁激发大大增强,相比,Tm $_3$ Sb $_3$ Mg $_2$ O $_{14}$,其中有少得多的无序。我们认为Zn $^{2+}$ /Mg $^{2+}$中Tm $^{3+}$离子的有效自旋引起低能磁激发,而随机占据的量决定了激发强度.这些结果提供了直接的证据,模仿的QSL引起的障碍。
英文摘要:
Quantum spin liquids (QSLs) are an exotic state of matter that is subject to extensive research. However, the relationship between the ubiquitous disorder and the QSL behaviors is still unclear. Here, by performing comparative experimental studies on two kagomé-lattice QSL candidates, Tm$_3$Sb$_3$Zn$_2$O$_{14}$ and Tm$_3$Sb$_3$Mg$_2$O$_{14}$, which are isostructural to each other but with strong and weak structural disorder, respectively, we show unambiguously that the disorder can induce spin-liquid-like features. In particular, both compounds show dominant antiferromagnetic interactions with a Curie-Weiss temperature of -17.4 and -28.7 K for Tm$_3$Sb$_3$Zn$_2$O$_{14}$ and Tm$_3$Sb$_3$Mg$_2$O$_{14}$, respectively, but remain disordered down to about 0.05 K. Specific heat results suggest the presence of gapless magnetic excitations characterized by a residual linear term. Magnetic excitation spectra obtained by inelastic neutron scattering (INS) at low temperatures display broad continua. All these observations are consistent with those of a QSL. However, we find in Tm$_3$Sb$_3$Zn$_2$O$_{14}$ which has strong disorder resulting from the random mixing of the magnetic Tm$^{3+}$ and nonmagnetic Zn$^{2+}$, that the low-energy magnetic excitations observed in the specific heat and INS measurements are substantially enhanced, compared to those of Tm$_3$Sb$_3$Mg$_2$O$_{14}$ which has much less disorder. We believe that the effective spins of the Tm$^{3+}$ ions in the Zn$^{2+}$/Mg$^{2+}$ sites give rise to the low-energy magnetic excitations, and the amount of the random occupancy determines the excitation strength. These results provide direct evidence of the mimicry of a QSL caused by disorder.
YCr6Ge6 as a Candidate Compound for a Kagome Metal
我们表明,YCr 6 Ge 6,包括一个由Cr原子组成的kagome晶格,是一个合理的候选化合物的kagome金属,预计表现出异常现象,如平带铁磁性。测量了YCr 6 Ge 6单晶的电阻率、磁化强度和热容,并进行了能带结构计算以研究其电子结构。居里-外斯的磁化率,T2电阻率的依赖性,和索末菲系数从计算值增加一倍的行为表明一个中等强的电子相关。有趣的是,面内电阻率是面间电阻率的两倍,这与分层结构的简单预期相反。能带结构的计算表明,在Γ点附近,在费米能级以下存在部分平坦带,属于Cr 3d 3 z2-r2带,可能决定了该化合物的性质。
Crystal Field Levels and Magnetic Anisotropy in the Kagome Compounds $\rm{Nd_3Sb_3Mg_2O_{14}}$, $\rm{Nd_3Sb_3Zn_2O_{14}}$, and $\rm{Pr_3Sb_3Mg_2O_{14}}$
The kagome staircase compounds Ni$_{3}$V$_{2}$O$_{8}$ and Co$_{3}$V$_{2}$O$_{8}$ studied with implanted muons
本文报道了可果美阶梯化合物Ni $_{3}$ V $_{2}$ O $_{8}$和Co $_{3}$ V $_{2}$ O $_{8}$的μ子自旋弛豫($μ^{+}$ SR)测量结果.这些材料的磁性行为可以用两个不等价的磁性离子位点来描述,称为脊柱位点和交叉结合位点。我们的$μ^{+}$ SR结果使我们能够单独探测这些位置中的每一个,揭示这些位置附近的局部磁场的分布。我们不仅能够确认的基础上提出的散装测量的各个阶段的磁结构,但也给在每个阶段的局部场分布的温度演变的洞察。
Charge density wave in kagome lattice intermetallic ScV6Sn6
拥有可果美晶格的材料因几何挫折所产生的不同磁性和电子状态而引起人们的兴趣。在$A$ V $_3$ Sb $_5$化合物($A$ = K、Rb、Cs)中,堆叠的钒kagome层产生不寻常的电荷密度波(CDW)和超导性。在这里,我们报告单晶生长和表征的ScV $_6$锡$_6$,六方HfFe $_6$锗$_6$型化合物,共享这个结构基序。在92 K处发现了一级相变。单晶X射线和中子衍射揭示了低于该温度的原子晶格的电荷密度波调制。这与在$A$ V $_3$ Sb $_5$化合物中观察到的结构模式明显不同,但在可果美金属中预期了这两种模式。不同的HfFe $_6$ Ge $_6$系列提供了更多的机会来调整ScV $_6$ Sn $_6$和探索可果美晶格材料中的密度波序。
Discovery of BKT correlations in the quantum kagome compound Cs$_2$Cu$_3$SnF$_{12}$
University of Zagreb(萨格勒布大学);Institute of Science Tokyo(东京科学研究所);Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, Université Grenoble Alpes, Université Toulouse, INSA-T(强磁场国家实验室,LNCMI-CNRS(UPR3228),EMFL,格勒诺布尔阿尔卑斯大学,图卢兹大学,INSA-T)
Magnetic correlations in the semimetallic hyper-kagome iridate Na3Ir3O8
本文用$_3$ Na NMR对一种掺杂量子自旋液体候选物--我们确定的内在行为的均匀\textbf{q} $ = 0$的磁化率通过移位测量和动力学响应通过探测自旋晶格弛豫率。在整个研究的温度范围内,磁化率是一致的半金属行为,虽然与电子带大幅修改的相关性。值得注意的是,存在于绝缘母体化合物Na $_4$ Ir $_3$ O $_8$中的反铁磁波动在所研究的化合物中存活。自旋动力学与120种显示短程相关性的$^o$激发模式一致。
Uncontrolled disorder effects in fabricating photonic quantum simulators on a kagome geometry: A projected-entangled pair state versus exact digonalization analysis
Hall effect on nontrivial quadrupole order in quasi-kagome compound URhSn
Institute for Solid State Physics (ISSP), University of Tokyo(东京大学固体物理研究所);Department of Physics, Mizoram University(米佐拉姆大学物理系);Institute for Materials Research (IMR), Tohoku University(东北大学物质材料研究所学);Advanced Science Research Center, Japan Atomic Energy Agency(日本原子能研究机构先进科学研究中心);Helmholtz-Zentrum Dresden-Rossendorf(德累斯顿-罗斯多夫亥姆霍兹中心)
Study of the electronic properties of topological kagome metals YV$_6$Sn$_6$ and GdV$_6$Sn$_6$
介绍了钒基可果美金属YV $_6$ Sn $_6$和GdV $_6$ Sn $_6$的合成和表征。X射线衍射,磁化强度,磁输运,和热容量测量揭示了一个理想的可果美网络的V-离子协调锡和分离的三角晶格平面的稀土离子。在GdV $_6$ Sn $_6$中检测到Gd自旋的低温、可能非共线的磁序的开始,而两种化合物中的V离子仍然是非共线的。密度泛函理论计算建模的能带结构的两种化合物,这可以被归类为$\mathbb{Z}_2$拓扑金属的顺磁状态。这两种化合物表现出高流动性,多带传输,并提出了一个有趣的平台,用于控制与$R$ -网站的亚晶格和非平凡的带拓扑结构与V-为基础的可果美网络相关的磁秩序之间的相互作用。我们的研究结果邀请其他$R$ V $_6$ Sn $_6$($R$ =稀土)变体的未来探索,其中这种相互作用可以通过$R$ -位点取代来调节。
Evidence of Mott Insulator with Thermally Induced Melting Behavior in Kagome Compound Nb3Cl8
International Center for Quantum Materials, School of Physics, Peking University(北京大学物理学院量子材料国际中心);Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology(北京理工大学物理学院先进光电量子结构测量教育部重点实验室量子物理中心);Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences(中国科学院物理研究所凝聚态物理国家实验室);Research Center for Electronic and Optical Materials, National Institute of Material Sciences(国立材料科学研究所电子与光学材料研究中心);Research Center for Materials Nanoarchitectonics, National Institute of Material Sciences(国立材料科学研究所材料纳米构造研究中心);School of Materials Science and Engineering, Peking University(北京大学材料科学与工程学院);State Key Laboratory for Mesoscopic Physics, Frontiers Science Centre for Nano-optoelectronics, School of Physics, Peking University(北京大学物理学院介观物理国家重点实验室纳米光电子前沿科学中心);Collaborative Innovation Center of Quantum Matter(量子物质协同创新中心)
Entanglement entropy and disorder operator at kagome deconfined quantum criticality
Hangzhou International Innovation Institute, Beihang University(北京航空航天大学杭州国际创新学院);Tianmushan Laboratory(天目山实验室);Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University(西湖大学理学院未来产业研究中心物理系);Institute of Natural Sciences, Westlake Institute for Advanced Study(西湖高等研究院自然科学院);Department of Physics, Chongqing University(重庆大学物理系)