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arXiv 2501.04494cond-mat.mes-hall
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周期驱动三聚体晶格中的反常拓扑边缘模

Anomalous topological edge modes in a periodically-driven trimer lattice

Mohammad Ghuneim, Raditya Weda Bomantara

AI总结:

本研究提出周期驱动三聚体扩展SSH模型,发现钉扎于半驱动频率的π模等反常边缘模,源于拓扑与手征对称性相互作用,并验证其对无序的鲁棒性。

摘要:

周期驱动系统因其能够建立超越静态对应物的丰富拓扑现象而享有长期声誉。在本工作中,我们提出并研究了一个每原胞含三个位点的周期驱动扩展Su-Schrieffer-Heeger模型,该模型通过将泡利矩阵替换为其$3\times 3$对应矩阵而获得。我们发现该系统在一系列参数窗口内支持多种边缘模,其中一些没有静态对应物。在这些边缘模中,特别引人关注的是那些被钉扎在特定准能量值上的模。这种准能量固定的边缘模源于拓扑与手征对称性之间的相互作用,而在三带静态模型中,由于唯一的具有手征对称性的能量值(即零)处存在体带,这类模通常不被预期出现。在我们的时间周期设置中,存在另一个具有手征对称性的准能量值,位于驱动频率的一半处,该值不被体带占据,因此可以承载受手征对称性保护的边缘模($\pi$模)。最后,我们验证了所有边缘模对空间无序的鲁棒性,并简要讨论了在实验中实现我们系统的前景。

英文摘要:

Periodically driven systems have a longstanding reputation for establishing rich topological phenomena beyond their static counterpart. In this work, we propose and investigate a periodically driven extended Su-Schrieffer-Heeger model with three sites per unit cell, obtained by replacing the Pauli matrices with their $3\times 3$ counterparts. The system is found to support a number of edge modes over a range of parameter windows, some of which have no static counterparts. Among these edge modes, of particular interest are those which are pinned at a specific quasienergy value. Such quasienergy-fixed edge modes arise due to the interplay between topology and chiral symmetry, which are typically not expected in a three-band static model due to the presence of a bulk band at the only chiral-symmetric energy value, i.e., zero. In our time-periodic setting, another chiral-symmetric quasienergy value exists at half the driving frequency, which is not occupied by a bulk band and could then host chiral-symmetry-protected edge modes ($π$ modes). Finally, we verify the robustness of all edge modes against spatial disorder and briefly discuss the prospect of realizing our system in experiments.

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。

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