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arXiv 1801.00697cond-mat.str-el
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弱相互作用拓扑绝缘体:量子临界性和重整化群方法

Weakly Interacting Topological Insulators: Quantum Criticality and Renormalization Group Approach

Wei Chen

摘要:

对于D维弱相互作用拓扑绝缘体在某些对称类中,拓扑不变量可以从D维或(D+1)维积分计算出,该积分是用单粒子格林函数表示的。基于曲率函数在拓扑相变处的发散性,我们证明了重整化群方法是如何绕过这些积分,并将必要的计算减少到仅对格林函数的计算,从而为在大参数空间中识别拓扑相变提供了一个数值有效的工具.该方法进一步揭示了一些统计方面的量子临界性在弱相互作用拓扑绝缘体,包括关联函数,临界指数,和标度律,可用于表征的拓扑相变驱动的相互作用或非相互作用参数。我们使用一维BDI类和二维A类Dirac模型,考虑电子-电子和电子-声子相互作用,证明了这些原理,并发现相互作用可以改变拓扑绝缘体的临界指数.

英文摘要:

For D-dimensional weakly interacting topological insulators in certain symmetry classes, the topological invariant can be calculated from a D- or (D+1)-dimensional integration over a certain curvature function that is expressed in terms of single-particle Green's functions. Based on the divergence of curvature function at the topological phase transition, we demonstrate how a renormalization group approach circumvents these integrations and reduces the necessary calculation to that for the Green's function alone, rendering a numerically efficient tool to identify topological phase transitions in a large parameter space. The method further unveils a number of statistical aspects related to the quantum criticality in weakly interacting topological insulators, including correlation function, critical exponents, and scaling laws, that can be used to characterize the topological phase transitions driven by either interacting or noninteracting parameters. We use 1D class BDI and 2D class A Dirac models with electron-electron and electron-phonon interactions to demonstrate these principles, and find that interactions may change the critical exponents of the topological insulators.

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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