论文标题
在Floquet二阶拓扑超导体中产生许多Majorana角落模式和多个相变
Generating many Majorana corner modes and multiple phase transitions in Floquet second-order topological superconductors
论文作者
论文摘要
$ d $ dimensional，$ n $ th级拓扑绝缘子或超导体的局部特征模式处于其$（d-n）$ - 尺寸边界（$ n \ n \ leq d $）。在这项工作中，我们将定期驾驶场应用于二维超导体，并获得各种各样的Floquet二阶拓扑超导体（SOTSC）阶段，其零是零和$π$ quasienergies的许多Majorana角模式。发现两个不同的浮雕SOTSC相通过三种可能的变换而分开，即，由于大量光谱间隙的关闭/重新打开而引起的拓扑相变，由于边缘光谱的闭合/重新打开而导致的拓扑相变，或者是完全不同的相位，而该相位是散装光谱的完全不同的相位。由于系统的驾驶和内在能量尺度之间存在强大的相互作用，所有发现的阶段和过渡都可以通过调整系统的单个跳跃参数高度控制。我们的发现不仅丰富了Floquet SOTSC阶段的可能形式，而且还提供了一个有效的方案，可以生成许多共存MajoraNa零和$π$ CORNER模式，这些模式可能会在Floquet量子计算中找到应用程序。
A $d$-dimensional, $n$th-order topological insulator or superconductor has localized eigenmodes at its $(d-n)$-dimensional boundaries ($n\leq d$). In this work, we apply periodic driving fields to two-dimensional superconductors, and obtain a wide variety of Floquet second-order topological superconducting (SOTSC) phases with many Majorana corner modes at both zero and $π$ quasienergies. Two distinct Floquet SOTSC phases are found to be separated by three possible kinds of transformations, i.e., a topological phase transition due to the closing/reopening of a bulk spectral gap, a topological phase transition due to the closing/reopening of an edge spectral gap, or an entirely different phase in which the bulk spectrum is gapless. Thanks to the strong interplay between driving and intrinsic energy scales of the system, all the found phases and transitions are highly controllable via tuning a single hopping parameter of the system. Our discovery not only enriches the possible forms of Floquet SOTSC phases, but also offers an efficient scheme to generate many coexisting Majorana zero and $π$ corner modes that may find applications in Floquet quantum computation.
