论文标题
在远程Su-Schrieffer-Heeger模型中的拓扑安德森绝缘阶段
Topological Anderson insulating phases in the long-range Su-Schrieffer-Heeger model
论文作者
论文摘要
在考虑下一个最近的邻居跳跃的远程Su-Schriffer-Heeger(SSH)模型中,其中展示了一个丰富的拓扑相图,其中包含绕组数字$ W = 0、1 $和$ 2 $。在存在障碍的情况下,在数值上计算出具有各种混乱强度的平均绕组数变化。我们发现该疾病驱动了相转换:$ w = 0 \ rightArrow 1,0 \ rightarrow 2 $,$ 1 \ rightarrow 2 $和$ 2 \ rightArrow 1 $,其中由疾病驱动的非零绕组数字称为拓扑式Anderson Anderson Inserson Inseruting(Tai)阶段。该远程SSH模型中的过渡机制通过定位长度和自我能量进行了研究。我们发现,定位长度在过渡点具有巨大的变化,并且通过进一步使用天生对自我能源的近似来获得相应的临界障碍强度。 $ w = 0 $至$ w = 1,2 $转换的来源归因于能量差距的重新归一化(第一天生近似),而从$ w = 1 $到$ w = 2 $的过渡,vice的过渡是强烈的散射(自稳定的近似近似)。自一致的诞生近似的结果表明,在热力学极限中,缝隙截止点不在具有局部边缘状态的系统的费米水平上。这与边缘状态的拓扑保护一致,因此,先前存在的边缘状态不受散布的保护。鉴于远程SSH模型的实验可行性,可以在实验中观察到预测的TAI相和过渡。
In the long-range Su-Schriffer-Heeger (SSH) model, in which the next nearest-neighbor hopping is considered, there exhibits a rich topological phase diagram that contains winding numbers $w=0, 1$, and $2$. In the presence of disorder, the change in mean winding number with various disorder strengths is numerically calculated. We find that the disorder drives phase transitions: $w=0 \rightarrow 1, 0 \rightarrow 2 $, $1 \rightarrow 2$ and $2 \rightarrow 1$, in which the non-zero winding numbers driven by disorder are called the topological Anderson insulating (TAI) phases. The transition mechanisms in this long-range SSH model are investigated by means of localization length and self-energy. We find that the localization length has a drastic change at the transition point, and the corresponding critical disorder strength is obtained by further using Born approximation to the self-energy. The origin for the $w = 0$ to $w = 1, 2$ transitions is attributed to the energy gap renormalization (first Born approximation), while for the transitions from $w=1$ to $w=2$ and vice versa are the strong scattering (self-consistent Born approximation). The result of self-consistent Born approximation suggests that in the thermodynamic limit, the gap closing point is not at the Fermi level for the system with localized edge states. This agrees with the topological protection of edge states, such that the pre-existent edge states are protected from being scattered into bulk. Given the experimental feasibility of the long-range SSH model, the predicted TAI phases and transitions could be observed in experiments.