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arXiv 2103.07203cond-mat.str-el
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脆性拓扑绝缘体中的Mott跃迁和磁性

Mott transition and magnetism in a fragile topological insulator

Ashish Joshi, Robert Peters

摘要:

利用动力学平均场论研究了电子关联对脆性拓扑的影响。脆弱的拓扑绝缘体(FTI)阻碍了指数局部化Wannier函数的形成,但可以通过添加某些微不足道的自由度来使它们变得微不足道。出于同样的原因,FTIs不主机的边缘状态之间的散装带在圆柱形边界条件下的安全保护流,但预计有一个脆弱的带和其他带在某些扭曲的边界条件下的频谱流。我们在这里分析常见的强相关性,如莫特绝缘体过渡和磁性,在一个已知的模型托管脆弱的拓扑结构的影响。我们表明,在这种情况下,脆弱的拓扑结构,随着扭曲的边界状态,是稳定的相互作用低于临界相互作用强度。超过这个相互作用强度,过渡到莫特绝缘相发生,扭曲的边界状态消失。此外,通过施加均匀磁场,脆弱的拓扑结构被破坏。然而,我们表明磁场可以诱导拓扑相变,将脆弱的拓扑绝缘体转化为陈氏绝缘体。最后,我们研究了脆性拓扑模型的铁磁解。

英文摘要:

We study the effects of electronic correlations on fragile topology using dynamical mean-field theory. Fragile topological insulators (FTIs) offer obstruction to the formation of exponentially localized Wannier functions, but they can be trivialized by adding certain trivial degrees of freedom. For the same reason, FTIs do not host symmetry-protected flow of edge states between bulk bands in cylindrical boundary conditions but are expected to have a spectral flow between the fragile bands and other bands under certain twisted boundary conditions. We here analyze commonly observed effects of strong correlations, such as the Mott-insulator transition and magnetism, on a known model hosting fragile topology. We show that in the nonmagnetic case, fragile topology, along with the twisted boundary states, is stable with interactions below a critical interaction strength. Above this interaction strength, a transition to the Mott insulating phase occurs, and the twisted boundary states disappear. Furthermore, by applying a homogeneous magnetic field, the fragile topology is destroyed. However, we show that a magnetic field can induce a topological phase transition which converts a fragile topological insulator to a Chern insulator. Finally, we study ferromagnetic solutions of the fragile topological model.

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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