Honeycomb lattice with multiorbital structure: Topological and quantum anomalous Hall insulators with large gaps

Zhang, Gufeng; Li, Yi; Wu, Congjun

doi:10.1103/physrevb.90.075114

Cited by 118 publications

(91 citation statements)

References 48 publications

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“…Because of the buckling structures of silicene, germanene and stanene, their corresponding nanotubes have gear-like structures, quite different from carbon nanotubes. The gear-like structures of nanotubes are presented in Fig .1 (a), in which the cross-section and side views are given for tin armchair (8,8) and zigzag (10,0) nanotubes, respectively. Due to the gear-like structures, there are two classes of atoms with small and large distance to the central axis, which are illustrated using different colors in Fig.…”

Section: Resultsmentioning

confidence: 99%

Band gap scaling laws in group IV nanotubes

Wang¹,

Fu²,

Guo³

et al. 2017

Nanotechnology

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By using the first-principles calculations, the band gap properties of nanotubes formed by group IV elements have been investigated systemically. Our results reveal that for armchair nanotubes, the energy gaps at K points in the Brillouin zone decrease as 1/r scaling law with the radii (r) increasing, while they are scaled by -1/r + C at Γ points, here, C is a constant. Further studies show that such scaling law of K points is independent of both the chiral vector and the type of elements. Therefore, the band gaps of nanotubes for a given radius can be determined by these scaling laws easily. Interestingly, we also predict the existence of indirect band gap for both germanium and tin nanotubes. Our new findings provide an efficient way to determine the band gaps of group IV element nanotubes by knowing the radii, as well as to facilitate the design of functional nanodevices.

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Section: Resultsmentioning

confidence: 99%

Band gap scaling laws in group IV nanotubes

Wang¹,

Fu²,

Guo³

et al. 2017

Nanotechnology

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“…For instance, stanene and its derivatives could support large-gap 2D quantum spin Hall (QSH) states and thus enable dissipationless electric conduction at room temperature 4,9 . Moreover, stanene could also provide other novel features, including enhanced thermoelectricity 5 , topological superconductivity 6 and near-room-temperature quantum anomalous Hall (QAH) effect 7 .…”

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confidence: 99%

Epitaxial growth of two-dimensional stanene

et al. 2015

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Following the first experimental realization of graphene, other ultrathin materials with unprecedented electronic properties have been explored, with particular attention given to the heavy group-IV elements Si, Ge and Sn. Two-dimensional buckled Si-based silicene has been recently realized by molecular beam epitaxy growth, whereas Ge-based germanene was obtained by molecular beam epitaxy and mechanical exfoliation. However, the synthesis of Sn-based stanene has proved challenging so far. Here, we report the successful fabrication of 2D stanene by molecular beam epitaxy, confirmed by atomic and electronic characterization using scanning tunnelling microscopy and angle-resolved photoemission spectroscopy, in combination with first-principles calculations. The synthesis of stanene and its derivatives will stimulate further experimental investigation of their theoretically predicted properties, such as a 2D topological insulating behaviour with a very large bandgap, and the capability to support enhanced thermoelectric performance, topological superconductivity and the near-room-temperature quantum anomalous Hall effect.

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“…We consider three different types of HgTe layers with superimposed honeycomb geometry and present atomistic tight-binding (TB) calculations of their conduction band structure that we accurately describe by a 16-band effective model. Such lattices take advantage of the multi-orbital degrees of freedom in the honeycomb setup, allied to the strong SOC 17 . The access to multi-orbital degrees of freedom allows for further manipulation of the topological properties.…”

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confidence: 99%

Topological states in multi-orbital HgTe honeycomb lattices

et al. 2015

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Research on graphene has revealed remarkable phenomena arising in the honeycomb lattice. However, the quantum spin Hall effect predicted at the K point could not be observed in graphene and other honeycomb structures of light elements due to an insufficiently strong spin–orbit coupling. Here we show theoretically that 2D honeycomb lattices of HgTe can combine the effects of the honeycomb geometry and strong spin–orbit coupling. The conduction bands, experimentally accessible via doping, can be described by a tight-binding lattice model as in graphene, but including multi-orbital degrees of freedom and spin–orbit coupling. This results in very large topological gaps (up to 35 meV) and a flattened band detached from the others. Owing to this flat band and the sizable Coulomb interaction, honeycomb structures of HgTe constitute a promising platform for the observation of a fractional Chern insulator or a fractional quantum spin Hall phase.

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Honeycomb lattice with multiorbital structure: Topological and quantum anomalous Hall insulators with large gaps

Cited by 118 publications

References 48 publications

Band gap scaling laws in group IV nanotubes

Band gap scaling laws in group IV nanotubes

Epitaxial growth of two-dimensional stanene

Topological states in multi-orbital HgTe honeycomb lattices

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