Electron fractionalization in two-dimensional graphenelike structures
Electron fractionalization in two-dimensional graphenelike structures
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DOI：
10.1103/physrevlett.98.186809
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发表时间：
2007-05-04
影响因子：
8.6
通讯作者：
Mudry, Christopher
中科院分区：
文献类型：
--
作者：
Hou, Chang-Yu;Chamon, Claudio;Mudry, Christopher
电子的分馏与拓扑结构密切相关。在一维系统中，在简并真空之间的磁区壁上存在分数电荷态。在二维系统中，量子霍尔流体中存在分馏化，其时间反转对称性被较大的外部磁场打破。最近，人们在寻找具有时间反转对称性的二维系统中的分馏化的例子方面付出了巨大的努力。在这封信中，我们证明了在类石墨烯结构上存在分数电荷的拓扑激发，其中准粒子用两种类型的狄拉克费米子来描述，并尊重时间反转对称性。拓扑零模在数学上类似于p波超导体中的分数阶涡旋。它们对应于狄拉克费米子质量相位的扭曲，类似于粒子物理学中的宇宙弦。
Electron fractionalization is intimately related to topology. In one-dimensional systems, fractionally charged states exist at domain walls between degenerate vacua. In two-dimensional systems, fractionalization exists in quantum Hall fluids, where time-reversal symmetry is broken by a large external magnetic field. Recently, there has been a tremendous effort in the search for examples of fractionalization in two-dimensional systems with time-reversal symmetry. In this Letter, we show that fractionally charged topological excitations exist on graphenelike structures, where quasiparticles are described by two flavors of Dirac fermions and time-reversal symmetry is respected. The topological zero modes are mathematically similar to fractional vortices in p-wave superconductors. They correspond to a twist in the phase in the mass of the Dirac fermions, akin to cosmic strings in particle physics.