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arXiv 1902.06545cond-mat.mes-hall
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相互作用对反常量子霍尔效应的影响

Influence of interactions on the anomalous quantum Hall effect

C. X. Zhang, M. A. Zubkov

摘要:

2 + 1维拓扑绝缘体在无相互作用时的反常量子霍尔电导率可以表示为由两点格林函数组成的拓扑不变量。对于非相互作用系统,该表达式是表示TKNN不变量的替代方式。人们普遍认为,在存在相互作用的情况下,霍尔电导率由相同的表达式给出,其中无相互作用的两点格林函数被考虑相互作用的完全两点格林函数所代替。然而,这一说法的证明至今没有给出。本文在$2+1$ D拓扑绝缘体的特殊紧束缚模型的框架下给出了这样一个证明.此外,我们还将研究扩展到$3+1$ D Weyl半金属。此前已知,在忽略相互作用的情况下,这些系统中的霍尔电导率通过两点格林函数以与$2+1$ D拓扑绝缘体类似的方式表示。同样,相互作用对这种表达的影响以前没有研究过。我们考虑这个问题的框架内的特定$3+1$ D模型的Weyl半金属中存在的接触四费米子相互作用和库仑相互作用。我们证明了(在单圈近似下),霍尔电导率的表达式与无相互作用情况下的相同,其中无相互作用的格林函数被包含相互作用的完整两点格林函数所取代.在此基础上讨论了伴随霍尔电导率变化的拓扑相变。

英文摘要:

The anomalous quantum Hall conductivity in the 2+1D topological insulators in the absence of interactions may be expressed as the topological invariant composed of the two - point Green function. For the noninteracting system this expression is the alternative way to represent the TKNN invariant. It is widely believed that in the presence of interactions the Hall conductivity is given by the same expression, in which the noninteracting two - point Green function is substituted by the complete two - point Green function with the interactions taken into account. However, the proof of this statement has not been given so far. In the present paper we give such a proof in the framework of the particular tight - binding models of the $2+1$ D topological insulator. Besides, we extend our consideration to the $3+1$ D Weyl semimetals. It was known previously that with the interactions neglected the Hall conductivity in those systems is expressed through the two - point Green function in the way similar to that of the $2+1$ D topological insulators. Again, the influence of interactions on this expression has not been investigated previously. We consider this problem within the framework of the particular $3+1$D model of Weyl semimetal in the presence of the contact four - fermion interactions and Coulomb interactions. We prove (up to the one - loop approximation), that the Hall conductivity is given by the same expression as in the noninteracting case, in which the noninteracting Green function is substituted by the complete two - point Green function with the interactions included. Basing on the obtained expressions we discuss the topological phase transitions accompanied by the change of Hall conductivity.

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