Theoretical Chemistry of α-Graphyne: Functionalization, Symmetry Breaking, and Generation of Dirac-Fermion Mass

Longuinhos, R.; Moujaes, Elie A.; Alexandre, Simone S.; Nunes, R. W.

doi:10.1021/cm501018w

Cited by 18 publications

(22 citation statements)

References 53 publications

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“…On the other hand, c-germanyne has a gap at the Fermi level, for which the zero density of states hinders the occurrence of spin-polarization. It would be noted that the antiferromagnetism causes a gap opening in c-silicyne at the K point as shown in Figure 5 c. Following the relativistic dispersion relation of for a massive Fermion [ 57 ], the opening gap is related to the Fermion mass as . Thus, the antiferromagnetism produces a mass for the Dirac fermions in c-silicyne, which is estimated to be 0.15 m 0 from the HSE gap of 0.71 eV ( m 0 is the mass of a free electron).…”

Section: Resultsmentioning

confidence: 97%

Unusual structural and electronic properties of porous silicene and germanene: insights from first-principles calculations

Ding

Wang

2015

Nanoscale Res Lett

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Using first-principles calculations, we investigate the geometric structures and electronic properties of porous silicene and germanene nanosheets, which are the Si and Ge analogues of α−graphyne (referred to as silicyne and germanyne). It is found that the elemental silicyne and germanyne sheets are energetically unfavourable. However, after the C-substitution, the hybrid graphyne-like sheets (c-silicyne/c-germanyne) possess robust energetic and dynamical stabilities. Different from silicene and germanene, c-silicyne is a flat sheet, and c-germanyne is buckled with a distinct half-hilled conformation. Such asymmetric buckling structure causes the semiconducting behaviour into c-germanyne. While in c-silicyne, the semimetallic Dirac-like property is kept at the nonmagnetic state, but a spontaneous antiferromagnetism produces the massive Dirac fermions and opens a sizeable gap between Dirac cones. A tensile strain can further enhance the antiferromagnetism, which also linearly modulates the gap value without altering the direct-bandgap feature. Through strain engineering, c-silicyne can form a type-II band alignment with the MoS 2 sheet. The combined c-silicyne/MoS 2 nanostructure has a high power conversion efficiency beyond 20% for photovoltaic solar cells, enabling a fascinating utilization in the fields of solar energy and nano-devices.

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Section: Resultsmentioning

confidence: 97%

Unusual structural and electronic properties of porous silicene and germanene: insights from first-principles calculations

Ding

Wang

2015

Nanoscale Res Lett

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“…In this regard, ab initio calculations on the electronic structure and the lattice stability of pristine and functionalized α-graphyne systems described two mechanisms leading to gap opening in the Dirac-Fermion electronic spectrum of these systems: symmetry-breaking connected with the lattice instabilities and partial incorporation of an sp 3 character in the bonding network. [29] Large carrier mobility was also observed for graph-2-yne sheets and nanoribbons, [30] for which different types of functionalization [31] and transverse electric fields [32] was implemented to tune the bandgap. Further details on the chemical properties and modifications of graph-n-ynes are reviewed in Section 4 herein.…”

Section: Electronic Propertiesmentioning

confidence: 98%

Multiscale Design of Graphyne‐Based Materials for High‐Performance Separation Membranes

et al. 2019

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By varying the number of acetylenic linkages connecting aromatic rings, a new family of atomically thin graph-n-yne materials can be designed and synthesized. Generating immense scientific interest This article is protected by copyright. All rights reserved. 2 due to its structural diversity and excellent physical properties, graph-n-yne has opened new avenues toward numerous promising engineering applications, especially for separation membranes with precise pore sizes. Having these tunable pore sizes in combination with their excellent mechanical strength to withstand high pressures, free-standing graph-n-yne is theoretically posited to be an outstanding membrane material for separating or purifying mixtures of either gases or liquids, rivaling or even dramatically exceeding the capabilities of current, state-of-art separation membranes. Computational modeling and simulations play an integral role in the bottom-up design and characterization of these graph-n-yne materials. Thus, here, the state of the art in modeling α-, β-, γ-, δ-, and 6,6,12-graphyne nanosheets for synthesizing graph-2-yne materials and 3D architectures thereof is discussed. Different synthesis methods are described and a broad overview of computational characterizations of graph-n-yne's electrical, chemical, and thermal properties is provided. Furthermore, a series of in-depth computational studies that delve into the specifics of graph-n-yne's mechanical strength and porosity, which confer superior performance for separation and desalination membranes, are reviewed.

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“…4.) The motivation to focus on these models is that, for D = 2, 3, they are known to be relevant to MOFs such as DCBP 3 Co 2 and DCA 3 Co 2 [71], α-graphyne [65][66][67][68], and TaS 2 [72,73]. (DCBP and DCA stand for dicyanobiphenyl and dicyanoanthracene, respectively).…”

Section: Examplesmentioning

confidence: 99%

“…1 for the schematic figure of the two-dimensional model. Such lattice structures are of interest because they are known to be realized in various organic-based materials, such as graphene superstructures [63,64], α-graphyne [65][66][67][68], and metal-organic frameworks (MOFs) [68][69][70][71], as well as some inorganic materials [72,73]. Recently, they were also discussed in the context of the square-root topological phases [74,75].…”

Section: Introductionmentioning

confidence: 99%

Flat-band solutions in $D$-dimensional decorated diamond and pyrochlore lattices: Reduction to molecular problem

Mizoguchi,

Katsura,

Maruyama

et al. 2021

Preprint

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Flat-band models have been of particular interest from both fundamental aspects and realization in materials. Beyond the canonical examples such as Lieb lattices and line graphs, a variety of tight-binding models are found to possess flat bands. However, analytical treatment of dispersion relations is limited, especially when there are multiple flat bands with different energies. In this paper, we present how to determine flat-band energies and wave functions in tight-binding models on decorated diamond and pyrochlore lattices in generic dimensions D ≥ 2. For two and three dimensions, such lattice structures are relevant to various organic and inorganic materials, and thus our method will be useful to analyze the band structures of these materials.

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Theoretical Chemistry of α-Graphyne: Functionalization, Symmetry Breaking, and Generation of Dirac-Fermion Mass

Cited by 18 publications

References 53 publications

Unusual structural and electronic properties of porous silicene and germanene: insights from first-principles calculations

Unusual structural and electronic properties of porous silicene and germanene: insights from first-principles calculations

Multiscale Design of Graphyne‐Based Materials for High‐Performance Separation Membranes

Flat-band solutions in $D$-dimensional decorated diamond and pyrochlore lattices: Reduction to molecular problem

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