论文标题
旋转的基态和自旋动力学的变异研究 - $ \ frac {1} {2} $ kagome Antymagnetic Heisenberg模型及其对Hebertsmithite Zncu $ _ {3} $（OH）
Variational study of the ground state and spin dynamics of the spin-$\frac{1}{2}$ Kagome antiferromagnetic Heisenberg model and its implication on Hebertsmithite ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$
论文作者
论文摘要
We find that the best RVB state of the spin-$\frac{1}{2}$ Kagome antiferromagnetic Heisenberg model(spin-$\frac{1}{2}$ KAFH) is described by a $Z_{2}$ gapped mean field ansatz, which hosts a mean field spinon dispersion very different from that of the widely studied $U(1)$狄拉克旋转液态。但是，我们发现从Gutzwiller投影的RPA（GRPA）理论计算出的物理自旋波动频谱实际上是无间隙的，几乎与$ U（1）$ u（1）$ dirac旋转液态状态相同。我们发现，这种特殊的行为可以归因于Kagome晶格上唯一的平面物理，这使得平均场Ansatz和RVB状态非注射态之间的映射。我们发现，旋转的自旋波动光谱 - $ \ frac {1} {2} $ kafh根本不是毫无疑问的，但其特征是一个突出的频谱峰值约为$ 0.25J $，$ \ mathbf {m mathbf {m} $ poots，它融入了延伸到2.7j $ 2.7j $ 2.7j $ 2.7j $的广泛延伸。基于这些结果，我们认为，光谱峰低于2 MEV，在Hebertsmithite Zncu $ _ {3} $（oh）$ _ {6} $ _ {6} $ cl $ _ {2} $中，hebertsmithite zncu $ _ {3} $ _ {2} $的光谱峰值归因于Cu $^$^2+IMPURITY ZN，位置应被理解为Kagome层的固有贡献。我们建议通过测量CU位点上的骑士移位而不是O位点来验证这种图片，而O位点几乎不明显，因为$ \ Mathbf {m} $点在Kagome晶格上最近的邻近旋转之间的强烈反铁磁相关，这是$ \ Mathbf {M} $点的旋转波动。
We find that the best RVB state of the spin-$\frac{1}{2}$ Kagome antiferromagnetic Heisenberg model(spin-$\frac{1}{2}$ KAFH) is described by a $Z_{2}$ gapped mean field ansatz, which hosts a mean field spinon dispersion very different from that of the widely studied $U(1)$ Dirac spin liquid state. However, we find that the physical spin fluctuation spectrum calculated from the Gutzwiller projected RPA(GRPA) theory above such an RVB state is actually gapless and is almost identical to that above the $U(1)$ Dirac spin liquid state. We find that such a peculiar behavior can be attributed to the unique flat band physics on the Kagome lattice, which makes the mapping between the mean field ansatz and the RVB state non-injective. We find that the spin fluctuation spectrum of the spin-$\frac{1}{2}$ KAFH is not at all featureless, but is characterized by a prominent spectral peak at about $0.25J$ around the $\mathbf{M}$ point, which is immersed in a broad continuum extending to $2.7J$. Based on these results, we argue that the spectral peak below 2 meV in the inelastic neutron scattering(INS) spectrum of Hebertsmithite ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$, which has been attributed to the contribution of Cu$^{2+}$ impurity spins occupying the Zn$^{2+}$ site, should rather be understood as the intrinsic contribution from the Kagome layer. We propose to verify such a picture by measuring the Knight shift on the Cu site, rather than the O site, which is almost blind to the spin fluctuation at the $\mathbf{M}$ point as a result of the strong antiferromagnetic correlation between nearest neighboring spins on the Kagome lattice.
