arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2607.04771cond-mat.mes-hall
收藏

局部缺陷与霍尔丹模型的拓扑结构

Local Defects and the Topology of the Haldane Model

Technion – Israel Institute of Technology(以色列理工学院)

Vishesh Makwana, Eric Akkermans

AI总结:

研究霍尔丹模型中局部缺陷与拓扑的相互作用,引入空位产生局域态,由\(\mathbb{Z}_2\)不变量分类,给出区分拓扑缺陷态与平凡缺陷的三个实验特征,与\(\mathbb{Z}_2\)预测定量相符。

摘要:

我们在十重分类框架内研究霍尔丹模型中局部缺陷与拓扑之间的相互作用。霍尔丹模型实现了由整数拓扑不变量(\(C = \pm1\))表征的陈绝缘相并支持手性边缘态。引入空位会在缺陷位置产生局域态,由\(\mathbb{Z}_2\)不变量\(\nu = C\cdot m,\mathrm{mod},2\)分类,其中\(m = N_A - N_B\)是空位构型的净子晶格不平衡:奇数不平衡存在受保护的零能量模式,偶数不平衡则没有。我们确定了三个独立的实验特征,将这些拓扑缺陷态与平凡(吸附原子)缺陷区分开来。首先,空位诱导的态在其波函数轮廓中表现出特征性位错,跟踪与缺陷相关的相位缠绕。其次,\(e/2\)的分数电荷在空位位置积累,而在吸附原子处没有这种电荷出现。第三,围绕空位诱导态循环的概率流与手性边缘态的方向相反,这与\(p\)波超导体中涡旋产生的电流反转直接类似。所有三个特征都与\(\mathbb{Z}_2\)预测在定量上一致。

英文摘要:

We investigate the interplay between local defects and topology in the Haldane model within the framework of the tenfold classification. The Haldane model realizes a Chern-insulating phase characterized by an integer topological invariant ($C=\pm 1$) and supports chiral edge states. Introducing vacancies gives rise to localized states at the defect sites, classified by a $\mathbb{Z}_2$ invariant $ν= C\cdot m,\mathrm{mod},2$, where $m=N_A-N_B$ is the net sublattice imbalance of the vacancy configuration: an odd imbalance hosts a protected zero-energy mode, whereas an even imbalance does not. We identify three independent experimental signatures that distinguish these topological defect states from trivial (adatom) defects. First, vacancy-induced states exhibit characteristic dislocations in their wavefunction profiles that track the phase winding associated with the defect. Second, a fractional charge of $e/2$ accumulates at vacancy sites, while no such charge appears at adatoms. Third, the probability current circulating around a vacancy-induced state flows in the opposite direction to that of chiral edge states, in direct analogy with the current reversal produced by a vortex in a $p$-wave superconductor. All three signatures are in quantitative agreement with the $\mathbb{Z}_2$ prediction.

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。

↑