Rise and fall of plaquette order in the Shastry-Sutherland magnet revealed by pseudofermion functional renormalization group
Rise and fall of plaquette order in the Shastry-Sutherland magnet revealed by pseudofermion functional renormalization group
复制标题
DOI：
10.1103/physrevb.105.l041115
复制
发表时间：
2021-11
影响因子：
3.7
通讯作者：
A. Keles;E. Zhao
中科院分区：
文献类型：
--
作者：
A. Keles;E. Zhao
Shastry-Sutherland模型作为阻挫磁性的典型例子已经被广泛研究。传统的观点认为，从元格价键序到Neel序的转变是直接的，并且可能实现超越金兹伯格-朗道范式的去限制量子临界点。然而，这种情况最近受到了密度矩阵重整化群改进的数值的挑战，该群提供了两个相之间存在狭窄无间隙自旋液体的证据。通过这一争议，并阐明这个复杂的参数制度从一个新的角度来看，我们报告的高分辨率功能重整化群分析的广义Shastry-Sutherland模型。当频率/能量标度从紫外线拨到红外线以产生零温度相图时，超过5000万个运行耦合的流动提供了自旋相关演化的详细图像。的单重态二聚体相出现作为一个固定点，尼尔秩序的特点是在顶点功能的发散，而进入和退出的元胞体顺序的过渡是伴随着明显的峰值元胞体的磁化率。在Neel序出现之前，元格序被抑制，这为$J_1/J_2\in（0.77，0.82）$的有限自旋液体区域提供了证据，在该区域流动是连续的，没有任何发散的迹象。
The Shastry-Sutherland model as a canonical example of frustrated magnetism has been extensively studied. The conventional wisdom has been that the transition from the plaquette valence bond order to the Neel order is direct and potentially realizes a deconfined quantum critical point beyond the Ginzburg-Landau paradigm. This scenario however was challenged recently by improved numerics from density matrix renormalization group which offers evidence for a narrow gapless spin liquid between the two phases. Prompted by this controversy and to shed light on this intricate parameter regime from a fresh perspective, we report high-resolution functional renormalization group analysis of the generalized Shastry-Sutherland model. The flows of over 50 million running couplings provide a detailed picture for the evolution of spin correlations as the frequency/energy scale is dialed from the ultraviolet to the infrared to yield the zero temperature phase diagram. The singlet dimer phase emerges as a fixed point, the Neel order is characterized by divergence in the vertex function, while the transition into and out of the plaquette order is accompanied by pronounced peaks in the plaquette susceptibility. The plaquette order is suppressed before the onset of the Neel order, lending evidence for a finite spin liquid region for $J_1/J_2\in (0.77,0.82)$, where the flow is continuous without any indication of divergence.