arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.01822cond-mat.str-el
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对Kitaev蜂窝模型热力学的进一步认识

Further insights into the thermodynamics of the Kitaev honeycomb model

Kexin Feng, Natalia B. Perkins, F. J. Burnell

摘要:

在这里,我们重新审视的Kitaev量子自旋液体实现的蜂窝晶格上的热力学。我们要解决两个主要问题:首先,我们调查是否有可观察到的拓扑Majorana边界模式的Kitaev蜂窝模型的热力学签名。我们认为,对于时间反演不变的情况下,剩余的低温熵是这些马约拉纳边缘模式的主要热力学签名,并验证使用大规模的蒙特卡罗模拟,这是目前在完整的Kitaev模型的剩余熵。当时间反演对称性被破坏时,马约拉纳边缘模式可能在更直接的热力学测量中观察到,例如比热,尽管只有在远低于体隙的温度下。其次,我们研究了Kitaev模型中磁通激发的能量学和相应的热力学特征。具体而言,我们研究了圆柱体和环面几何形状的磁通相互作用的数值,并量化其对Kitaev自旋液体的热力学的影响,通过使用多项式拟合的平均通量能量作为通量密度的函数,并将其外推到热力学极限。通过比较这个模型的蒙特卡罗模拟,我们发现磁通相互作用有显着的定量影响的形状和低温峰的比热。

英文摘要:

Here we revisit the thermodynamics of the Kitaev quantum spin liquid realized on the honeycomb lattice. We address two main questions: First, we investigate whether there are observable thermodynamic signatures of the topological Majorana boundary modes of the Kitaev honeycomb model. We argue that for the time-reversal invariant case the residual low-temperature entropy is the primary thermodynamic signature of these Majorana edge modes, and verify using large-scale Monte Carlo simulations that this residual entropy is present in the full Kitaev model. When time-reversal symmetry is broken, the Majorana edge modes are potentially observable in more direct thermodynamic measurements such as the specific heat, though only at temperatures well below the bulk gap. % Second, we study the energetics, and the corresponding thermodynamic signatures, of the flux excitations in the Kitaev model. Specifically, we study the flux interactions on both cylinder and torus geometries numerically, and quantify their impact on the thermodynamics of the Kitaev spin liquid by using a polynomial fit for the average flux energy as a function of flux density and extrapolating it to the thermodynamic limit. By comparing this model to Monte Carlo simulations, we find that flux interactions have a significant quantitative impact on the shape and the position of the low-temperature peak in the specific heat.

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