Buried topological edge state associated with interface between topological band insulator and Mott insulator
Buried topological edge state associated with interface between topological band insulator and Mott insulator
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与拓扑带绝缘体和莫特绝缘体之间的界面相关的掩埋拓扑边缘态
DOI：
10.1103/physrevb.90.205134
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发表时间：
2014
影响因子：
3.7
通讯作者：
A. Liebsch
中科院分区：
文献类型：
--
作者：
H. Ishida;A. Liebsch
用层动力学平均场理论研究了拓扑带绝缘体和Mott绝缘体界面处的电子结构。为了表示这些系统的体相，我们使用广义Bernevig-Hughes-Zhang模型，该模型除了包含导致能带反转的自旋-轨道耦合项之外，还包含Hubbard样的现场库仑能。拓扑和莫特绝缘阶段分别通过适当地选择较小和较大的值来实现。正如预期的那样，界面被发现是金属，因为本地化的边缘状态。然而，当莫特绝缘体中的库仑能量接近临界值时，这种边缘状态在莫特绝缘体深处而不是在界面处表现出最大振幅。这一发现对应于一种新型的邻近效应引起的相邻的拓扑带绝缘体，并表明，作为一个结果的自旋轨道耦合内的莫特绝缘体，几个层附近的接口转换从莫特绝缘相的拓扑绝缘相。此外，我们认为，普通的邻近效应，即近藤峰是由相邻的金属态在莫特绝缘体中诱导，伴随着一个额外的反向邻近效应，近藤峰引起的状态密度在相邻的金属层的增强。
The electronic structure at the interface between a topological band insulator and a Mott insulator is studied within layer dynamical mean field theory. To represent the bulk phases of these systems, we use the generalized Bernevig-Hughes-Zhang model that incorporates the Hubbard-like on-site Coulomb energyin addition to the spin-orbit coupling term that causes band inversion. The topological and Mott insulating phases are realized by appropriately choosing smaller and larger values of, respectively. As expected, the interface is found to be metallic because of the localized edge state. When the Coulomb energy in the Mott insulator is close to the critical value, however, this edge state exhibits its largest amplitude deep within the Mott insulator rather than at the interface. This finding corresponds to a new type of proximity effect induced by the neighboring topological band insulator and demonstrates that, as a result of spin-orbit coupling within the Mott insulator, several layers near the interface convert from the Mott insulating phase to a topological insulating phase. Moreover, we argue that the ordinary proximity effect, whereby a Kondo peak is induced in a Mott insulator by neighboring metallic states, is accompanied by an additional reverse proximity effect, by which the Kondo peak gives rise to an enhancement of the density of states in the neighboring metallic layer.