Probing a topological quantum critical point in semiconductor-superconductor heterostructures
Probing a topological quantum critical point in semiconductor-superconductor heterostructures
复制标题
探讨半导体-超导异质结构中的拓扑量子临界点
DOI：
10.1103/physrevb.85.155302
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发表时间：
2011
影响因子：
3.7
通讯作者：
S. Sarma
中科院分区：
文献类型：
--
作者：
S. Tewari;J. Sau;V. Scarola;Chuanwei Zhang;S. Sarma
拓扑量子临界点（TQCP）非平凡侧的量子基态具有独特的性质，使它们成为量子信息应用的有吸引力的候选者。最近的一个例子是在半导体平台上的s波超导性，它通过TQCP被外部塞曼场调谐到拓扑超导（TS）状态。尽管TS态有许多吸引人的特征，但TQCP本身并没有打破任何对称性，使得在传统的体测量中无法区分TS态和常规超导体。在这里，我们表明，对于半导体TQCP这个问题可以克服跟踪合适的整体输运性质的拓扑量子临界制度本身。普适的低能有效理论和相关的非线性的标度形式也提供了一个有用的理论框架，在其中理解的拓扑结构中的异质结构的转变。基于我们的理论，提出了具体的体测量，以表征在半导体异质结构中的新的TQCP。
Quantum ground states on the non-trivial side of a topological quantum critical point (TQCP) have unique properties that make them attractive candidates for quantum information applications. A recent example is provided by s-wave superconductivity on a semiconductor platform, which is tuned through a TQCP to a topological superconducting (TS) state by an external Zeeman field. Despite many attractive features of TS states, TQCPs themselves do not break any symmetries, making it impossible to distinguish the TS state from a regular superconductor in conventional bulk measurements. Here we show that for the semiconductor TQCP this problem can be overcome by tracking suitable bulk transport properties across the topological quantum critical regime itself. The universal low-energy effective theory and the scaling form of the relevant susceptibilities also provide a useful theoretical framework in which to understand the topological transitions in semiconductor heterostructures. Based on our theory, specific bulk measurements are proposed here in order to characterize the novel TQCP in semiconductor heterostructures.