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Ai L.-Y.,Hebei Normal University | Ai L.-Y.,University of Science and Technology of China | Zhao H.-Y.,Hebei Normal University | Zhao H.-Y.,National Key Laboratory for Materials Simulation and Design | And 4 more authors.
Solid State Communications | Year: 2017

The stability and electronic structures of copper silicide nanotubes (CuSiNTs) are calculated using first-principles density functional theory. Here these CuSiNTs of various different diameters, chiral vectors and morphologies were obtained by rolling up a novel two-dimensional hypercoordinated Cu2Si monolayer with high stability (Yang et al., J. Am. Chem. Soc. 137 (2015) 2757−2762). Electronic structure calculations showed that these CuSiNTs are conductors independent of their chiral vectors, diameters and morphologies. In addition, molecular dynamics (MD) simulations of the (6, 0) tube and the (8, 4) tube were performed. It was found that the (8, 4) tube has very good thermal stability and that its structure does not break down during MD simulations at initial temperatures up to 1500 K. Based on their electrical conductivity and good thermal stability, these CuSiNTs are promising candidates to envision application as metallic connections in nanoscale electronic devices. © 2017


Wang J.,Hebei Normal University | Wang J.,CAS Institute of Semiconductors | Zhao H.-Y.,Beijing Computational Science Research Center | Liu Y.,Hebei Normal University | Liu Y.,National Key Laboratory for Materials Simulation and Design
ChemPhysChem | Year: 2014

Similar to carbon-based graphene, fullerenes and carbon nano-tubes, boron atoms can form sheets, fullerenes, and nano-tubes. Here we investigate several of these novel boron structures all based on the boron double ring within the framework of density functional theory. The boron sheet is found to be metallic and flat in its ground state. The spherical boron cage containing 180 atoms is also stable and has I symmetry. Stable nanotubes are obtained by rolling up the boron sheet, and all are metallic. The hydrogen storage capacity of boron nano-structures is also explored, and it is found that Li-decorated boron sheets and nanotubes are potential candidates for hydrogen storage. For Li-decorated boron sheets, each Li atom can adsorb a maximum of 4H2 molecules with gd = 7.892 wt%. The hydrogen gravimetric density increases to gd= 12.309 wt% for the Li-decorated (0,6) boron nanotube. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Yang H.-C.,Hebei Normal University | Wang J.,Hebei Normal University | Liu Y.,Hebei Normal University | Liu Y.,National Key Laboratory for Materials Simulation and Design
Journal of Applied Physics | Year: 2014

The decoration of silicane using 16 different metal adatoms and the adsorption of small molecules are studied using first-principles calculations. Of the 16 metal adatoms, Li, Na, K, Ca, In, and Sc show a larger binding energy with silicane than their corresponding cohesive energy in the bulk, which suggests they can form 2D layers on the surface of silicane. The band analysis indicates that decoration with metal atoms can effectively tailor the electronic properties of silicane. The adsorption for hydrogen and carbon monoxide on Li-silicane system demonstrates that each Li atom can adsorb a maximum of five H2 or four CO molecules with the average adsorption energy of 0.18 and 0.23 eV/atom, respectively. The calculated results suggest that metal-silicane systems can provide more information for applications as hydrogen-storage or environment-protection materials. © 2014 AIP Publishing LLC.


Wang J.,Hebei Normal University | Wang J.,National Key Laboratory for Materials Simulation and Design | Wang J.,CAS Institute of Semiconductors | Liu Y.,Hebei Normal University | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2010

A metal-encapsulating silicon fullerene, Eu@Si20, has been predicted by density functional theory to be by far the most stable fullerene-like silicon structure. The Eu@Si20 structure is a dodecahedron with D2h symmetry in which the europium atom occupies the center site. The calculated results show that the europium atom has a large magnetic moment of nearly 7.0 Bohr magnetons. In addition, it was found that a stable "pearl necklace" nanowire, constructed by concatenating a series of Eu@Si20 units, with the central europium atom, retains the high spin moment. The magnetic structure of the nanowire indicates potential applications in the fields of spintronics and high-density magnetic storage. © 2010 the Owner Societies.


Zhao H.-Y.,Hebei Normal University | Zhao H.-Y.,National Key Laboratory for Materials Simulation and Design | Wang J.,Hebei Normal University | Wang J.,National Key Laboratory for Materials Simulation and Design | And 4 more authors.
Physical Chemistry Chemical Physics | Year: 2013

The Kelvin problem, how to partition three-dimensional space into cells of equal volume with minimal area, is a fascinating one. Aggregations of bubbles are naturally physical illustrations of the Kelvin problem. And the superconductor Na8Si46 as an inspiration leads to an amazing discovery of the Weaire-Phelan (WP) structure of foam-the optimal solution to the Kelvin problem to date. Here based on the structural similarity between sp3-bonded silicon allotropes and the solutions to the Kelvin problem, a series of new sp3-hybridization silicon allotropes, named "Kelvin Silicons", are presented. Furthermore, the structural stability and electronic properties of these new silicon allotropes are investigated using density-functional theory (DFT) calculations. The results show that Kelvin Silicons are structurally stable semiconductors with indirect bandgaps in the range of 0.17-1.40 eV, and their bulk moduli are about 75.9-88.5% that of the diamond phase. The simulated X-ray diffraction spectra of the new silicon crystalline structures would provide more information for possible experimental observations and synthesis. © 2013 the Owner Societies.


Li J.,Hebei Normal University | Li J.,CAS Institute of Semiconductors | Wang J.,Hebei Normal University | Wang J.,National Key Laboratory for Materials Simulation and Design | And 4 more authors.
Journal of Physical Chemistry C | Year: 2013

A europium-encapsulating silicon nanotube, Eu2@Si30, has been predicted by density functional theory. Electronic structure analysis shows that in Si-Si chemical bonds there exist sp2-like hybridizations induced by the europium atoms, and the hybridizations evidently enhance the stability of the silicon nanotube. Moreover, the nanotube of Eu 2@Si30, with D5h symmetry, retains a high spin moment of 10 μB. On the basis of the Eu2Si 30Tube, a stable magnetic silicon nanotube (SiNT) was obtained, and it is found to be metallic. Similar to the predictions and speculation of Daedalus, the new magnetic SiNT may have potential applications in the fields of spintronics and high-density magnetic storage. © 2013 American Chemical Society.


Wang J.,Hebei Normal University | Wang J.,CAS Institute of Semiconductors | Ma H.-M.,Hebei Normal University | Liu Y.,Hebei Normal University | Liu Y.,National Key Laboratory for Materials Simulation and Design
Nanoscale | Year: 2016

An exceptionally stable hollow cage containing 20 scandium atoms and 60 carbon atoms has been identified. This Sc20C60 molecular cluster has a Th point group symmetry and a volleyball-like shape that we refer to below as "Volleyballene". Electronic structure analysis shows that the formation of delocalized π bonds between Sc atoms and the neighboring pentagonal rings made of carbon atoms is crucial for stabilizing the cage structure. A relatively large HOMO-LUMO gap (∼1.4 eV) was found. The results of vibrational frequency analysis and molecular dynamics simulations both demonstrate that this Volleyballene molecule is exceptionally stable. © 2016 The Royal Society of Chemistry.


Zhao H.-Y.,Hebei Normal University | Zhao H.-Y.,National Key Laboratory for Materials Simulation and Design | Wang J.,Hebei Normal University | Wang J.,National Key Laboratory for Materials Simulation and Design | And 4 more authors.
Journal of Chemical Physics | Year: 2013

As childrens toys, soap bubbles also underpin many important scientific questions. What is the most efficient structure for foam? - the Kelvin problem, has been one of the most intriguing science and widely discussed over the past hundred years. Soap bubbles frameworks have similar topology with sp 3-bonded carbon or silicon allotropes, e.g., Weaire-Phelan foam and superconducting clathrate Na8Si46. By looking at the most efficient structure for foams, we construct a series of new carbon allotropes, named Kelvin carbons. Unexpectedly, all 11 Kelvin carbons are structurally stable wide-bandgap semiconductors, and their densities and their intrinsic hardnesses are both about 81-87 that of diamond. The seventh state of Kelvin carbons, KVII, is a very low energy carbon structure after graphite, diamond, lonsdaleite, and type-II carbon clathrate. Kelvin carbons, which constitute a bridge between macro-foams and micro-carbons, together with recently proposed novel carbon phases can enrich the study of carbon allotropes. © 2013 AIP Publishing LLC.


Wang J.,Hebei Normal University | Wang J.,CAS Institute of Semiconductors | Liu Y.,Hebei Normal University | Liu Y.,National Key Laboratory for Materials Simulation and Design | Li Y.-C.,Hebei Normal University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010

The configurations, stability, and electronic structure of AuSin (n = 1 - 16) clusters have been investigated within the framework of the density functional theory at the B3PW91/LanL2DZ and PW91/DNP levels. The results show that the Au atom begins to occupy the interior site for cages as small as Si11 and for Si12 the Au atom completely falls into the interior site forming Au@Si12 cage. A relatively large embedding energy and small HOMO-LUMO gap are also found for this Au@Si12 structure indicating enhanced chemical activity and good electronic transfer properties. All these make Au@Si12 attractive for cluster-assembled materials. © 2010 Elsevier B.V. All rights reserved.


Ma Q.-M.,Hebei Normal University | Ma Q.-M.,National Key Laboratory for Materials Simulation and Design | Xie Z.,Hebei Normal University | Wang B.-R.,Hebei University of Science and Technology | And 3 more authors.
Solid State Communications | Year: 2011

The geometries, electronic structures and magnetic moments of the Fe nCr (n=112) clusters have been systematically investigated using all-electron density functional theory. For the lowest-energy structures of FenCr, the single Cr atom sits on the surface for all clusters up to n=10. For n=11 and n=12 the Cr atom falls into the interior site. For Fe nCr (n=18,1012), the local moment of the Fe atoms is found to align antiferromagnetically with respect to that of the Cr atom, while for Fe 9Cr, the local moments of the Fe atoms are ferromagnetic with respect to that of the Cr atom. © 2011 Elsevier Ltd. All rights reserved.

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