Fractional topological excitations and quantum phase transition in a bilayer two-dimensional electron gas adjacent to a superconductor film
Fractional topological excitations and quantum phase transition in a bilayer two-dimensional electron gas adjacent to a superconductor film
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邻近超导薄膜的双层二维电子气中的分数拓扑激发和量子相变
DOI：
10.1103/physrevb.81.125301
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发表时间：
2009-09
影响因子：
3.7
通讯作者：
Ping Zhang
中科院分区：
文献类型：
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作者：
N. Hao;W. Zhang;Z. Wang;Y. Wang;Ping Zhang
我们研究了双层二维电子气（2DEG）与具有钉扎涡旋晶格的II型超导薄膜相邻的情况。我们发现，随着层间隧穿的增加，半填充系统呈现出三个阶段：带隙相I（拓扑绝缘体），无隙临界相II（金属），带隙相III（带绝缘体）。相位I/III的总霍尔电导为2/0 e（2）/h，并且在相位II中具有非量子化值。由于系统的拓扑性质，这三个相的激发（对拓扑缺陷的响应，局部涡旋缺陷）表现出不同的行为，包括相I中每层的分数电荷e/2。而在四分之一填充的情况下，系统经历了从金属相到拓扑绝缘体相的量子相变。
We study a bilayer two-dimension-electron-gas (2DEG) adjacent to a type-II superconductor thin film with a pinned vortex lattice. We find that with increasing interlayer tunneling, the system of half-filling presents three phases: gapped phase-I (topological insulator), gapless critical phase-II (metal), and gapped phase-III (band insulator). The total Hall conductance for phase-I/III is 2/0 e(2)/h, and has nonquantized values in phase-II. The excitation (response to topological defect, a local vortex defect) in these three phases shows different behaviors due to the topological property of the system, including fractional charge e/2 for each layer in phase-I. While in the case of quarter-filling, the system undergoes a quantum phase transition from metallic phase to topological insulator phase.
DOI：
10.1017/cbo9780511973765
发表时间：
1999-04
期刊：
--
影响因子：
--
作者：
Subir Sachdev
通讯作者：
Subir Sachdev