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arXiv 2209.03344cond-mat.str-el
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三角晶格上 $S=1/2$ Heisenberg反铁磁体中对称破缺相与液相的动力学特征

Dynamical Signatures of Symmetry Broken and Liquid Phases in an $S=1/2$ Heisenberg Antiferromagnet on the Triangular Lattice

Markus Drescher, Laurens Vanderstraeten, Roderich Moessner, Frank Pollmann

AI总结:

利用大规模矩阵积态模拟计算三角晶格 $J_1-J_2$ Heisenberg模型的动力学自旋结构因子,揭示有序相磁振子规避衰变及自旋液相的Dirac单极子激发特征。

摘要:

我们给出了由大规模矩阵积态模拟得到的、三角晶格上反铁磁自旋 $\frac{1}{2}$ 的 $J_1-J_2$ Heisenberg模型的动力学自旋结构因子。反铁磁最近邻与次近邻相互作用的结合所导致的高度阻挫产生了丰富的相图。我们分别在 $120^{\circ}$ 有序相以及 $J_2/J_1=0.125$ 处公认的自旋液相中分辨了低能激发。在有序相中,我们观察到最低磁振子支的规避衰变,证明了该现象在无能隙激发存在时的稳健性。我们在自旋液相中的发现与无带隙Dirac自旋液体的场论预测相吻合,特别是关于Brillouin区角点处低位单极子激发的图像。我们还评述了基于动力学结构因子区分邻近液相与固相可能遇到的实际困难。

英文摘要:

We present the dynamical spin structure factor of the antiferromagnetic spin-$\frac{1}{2}$ $J_1-J_2$ Heisenberg model on a triangular lattice obtained from large-scale matrix-product state simulations. The high frustration due to the combination of antiferromagnetic nearest and next-to-nearest neighbour interactions yields a rich phase diagram. We resolve the low-energy excitations both in the $120^{\circ}$-ordered phase and in the putative spin liquid phase at $J_2/J_1 = 0.125$. In the ordered phase, we observe an avoided decay of the lowest magnon-branch, demonstrating the robustness of this phenomenon in the presence of gapless excitations. Our findings in the spin-liquid phase chime with the field-theoretical predictions for a gapless Dirac spin liquid, in particular the picture of low-lying monopole excitations at the corners of the Brillouin zone. We comment on possible practical difficulties of distinguishing proximate liquid and solid phases based on the dynamical structure factor.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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