Wang R, Yang X M, Song Z
School of Physics, Nankai University, Tianjin 300071, People's Republic of China.
J Phys Condens Matter. 2021 Jul 9;33(36). doi: 10.1088/1361-648X/ac0d86.
We investigate localization properties of two-coupled uniform chains (ladder) with quasiperiodic modulation on interchain coupling strength. We demonstrate that this ladder is equivalent to two Aubry-André chains when two legs are symmetric. Analytical and numerical results indicate the appearance of mobility edges in asymmetric ladder systems. We propose an easy-to-engineer quasiperiodic Moiré superlattice ladder system comprising two-coupled uniform chains. An irrational lattice constant difference results in a quasiperiodic structure. Numerical simulations indicate that such a system supports the existence of mobility edges. Furthermore, we demonstrate that the mobility edges can be detected through a dynamical method, that is based on the measurement of survival probability in the presence of a single imaginary negative potential. The results provide insights into localization transitions and mobility edges in experiments.
我们研究了链间耦合强度具有准周期调制的双耦合均匀链（梯子）的局域化特性。我们证明，当两条链腿对称时，这种梯子等效于两条奥布里 - 安德烈链。分析和数值结果表明，在非对称梯子系统中出现了迁移率边缘。我们提出了一种易于构建的准周期莫尔超晶格梯子系统，它由双耦合均匀链组成。无理数晶格常数差导致了准周期结构。数值模拟表明，这样的系统支持迁移率边缘的存在。此外，我们证明可以通过一种动力学方法检测迁移率边缘，该方法基于在存在单个虚数负势时对生存概率的测量。这些结果为实验中的局域化转变和迁移率边缘提供了见解。
