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arXiv 2103.02624cond-mat.str-el
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相互作用拓扑绝缘体单粒子格林函数的基本能带表示

Elementary band representations for the single-particle Green's function of interacting topological insulators

Dominik Lessnich, Stephen M. Winter, Mikel Iraola, Maia G. Vergniory, Roser Valentí

摘要:

我们讨论的适用性基本能带表示(EBRs)诊断空间和时间反转对称性保护的拓扑相位在相互作用的绝缘体中的单粒子格林函数。我们这样做,考虑一个辅助的非相互作用系统$H_{\textrm{T}}(\mathbf{k}) = -G^{-1}(0, \mathbf{k})$,称为拓扑哈密顿量,其频带可以标记的EBRs。如果(i)零频率处的谱函数中的间隙闭合,(ii)格林函数在零频率处具有零,或(iii)格林函数破坏保护对称性,则该标记是稳定的。我们演示了使用EBRs应用到格林函数的一维苏-Schrieffer-Heeger模型与哈伯德相互作用,我们解决了有限数量的单位细胞的精确对角化。最后,使用EBR的格林函数诊断所谓的对称性保护的拓扑相位进行了讨论,但仍然是一个悬而未决的问题。

英文摘要:

We discuss the applicability of elementary band representations (EBRs) to diagnose spatial- and time-reversal-symmetry protected topological phases in interacting insulators in terms of their single-particle Green's functions. We do so by considering an auxiliary non-interacting system $H_{\textrm{T}}(\mathbf{k}) = -G^{-1}(0, \mathbf{k})$, known as the topological Hamiltonian, whose bands can be labeled by EBRs. This labeling is stable if neither (i) the gap in the spectral function at zero frequency closes, (ii) the Green's function has a zero at zero frequency or (iii) the Green's function breaks a protecting symmetry. We demonstrate the use of EBRs applied to the Green's function on the one-dimensional Su-Schrieffer-Heeger model with Hubbard interactions, which we solve by exact diagonalization for a finite number of unit cells. Finally, the use of EBRs for the Green's function to diagnose so-called symmetry protected topological phases is discussed, but remains an open question.

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