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arXiv 1102.3282cond-mat.mes-hallmath-phmath.MPquant-ph
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周期condensed matter系统的局域拓扑相变

Local topological phase transitions in periodic condensed matter systems

Jan Carl Budich, Björn Trauzettel

摘要:

周期性凝聚态系统的拓扑性质是其布里渊区的整体特征。相反,有效低能理论的有效性通常限于BZ中的高对称点附近。我们得到一个一般的标准下,控制参数的拓扑相变局部拓扑缺陷在任意小的邻域中的一个单一的点在$k$ -空间接近其临界值。这样的局部相变是与一个Dirac-like间隙关闭点,而平坦的带过渡是不本地化的$k$空间。这种机制及其局限性说明与实验相关的例子,如碲化汞/碲化镉量子阱和双层石墨烯纳米结构的帮助。

英文摘要:

Topological properties of a periodic condensed matter system are global features of its Brillouin zone (BZ). In contrast, the validity of effective low energy theories is usually limited to the vicinity of a high symmetry point in the BZ. We derive a general criterion under which the control parameter of a topological phase transition localizes the topological defect in an arbitrarily small neighbourhood of a single point in $k$-space upon approaching its critical value. Such a local phase transition is associated with a Dirac-like gap closing point, whereas a flat band transition is not localized in $k$-space. This mechanism and its limitations are illustrated with the help of experimentally relevant examples such as HgTe/CdTe quantum wells and bilayer graphene nanostructures.

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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