Free standing double walled boron nanotubes

Sebetci, Ali; Mete, Ersen; Boustani, İhsan

doi:10.1016/j.jpcs.2008.02.014

Cited by 18 publications

(11 citation statements)

References 40 publications

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“…The existence of quasi-planar [7] and tubular [8] boron clusters was predicted theoretically and confirmed more recently experimentally [9,10]. In addition, double-walled boron nanotubes were predicted to be highly stable [11]. These authors found that the interaction between the walls in form of σ-bonds increases the stability of the system in opposite to the carbon nanotubes where the walls are connected by Van-der-Waals forces only, in which no chemical bonds are formed among the neighboring walls.…”

Section: Introductionsupporting

confidence: 60%

Novel spherical boron clusters and structural transition from 2D quasi-planar structures to 3D double-rings

Mukhopadhyay

Pandey

et al. 2009

J. Phys.: Conf. Ser.

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Based on ab initio quantum-chemical and density functional methods we determined the geometry, electronic and structural properties of three cluster-families: boron spheres, double-rings and quasi-planars up to a cluster size of 122 atoms. The most stable structure is the B100 sphere showing similar shape but more stability than the B80 cage recently proposed by Yakobson et al [PRL 98, 166804 (2007)]. In addition we compared the stability of the three cluster families to each other, and reported the structural transition from 2D quasiplanar clusters to 3D double-rings. This transition occurs between the B16 and B19 clusters.

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Section: Introductionsupporting

confidence: 60%

Novel spherical boron clusters and structural transition from 2D quasi-planar structures to 3D double-rings

Mukhopadhyay

Pandey

et al. 2009

J. Phys.: Conf. Ser.

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“…While at least 16 forms of boron (some of which were probably impurity-stabilized) have been reported, the existence as pure polymorphs of boron has been established for the α rhombohedral, β rhombohedral, two tetragonal phases, and the recently discovered orthorhombic highpressure partially ionic γ phase [2]. Boron has been investigated both theoretically and experimentally as bulk boron, nanotubes, clusters, quasi planar, monolayer, and bilayer sheets [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Novel boron nanobelts or nanowires have been successfully synthesized [13,14], and experimentally shown to be semimetals or narrow-gap semiconductors, but the exact atomic structures are still not fully resolved [14].…”

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confidence: 99%

Semimetallic Two-Dimensional Boron Allotrope with Massless Dirac Fermions

et al. 2014

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It has been widely accepted that planar boron structures, composed of triangular and hexagonal motifs are the most stable two dimensional (2D) phases and likely precursors for boron nanostructures. Here we predict, based on ab initio evolutionary structure search, novel 2D boron structure with non-zero thickness, which is considerably, by 50 meV/atom lower in energy than the recently proposed α-sheet structure and its analogues. In particular, this phase is identified for the first time to have a distorted Dirac cone, after graphene and silicene the third elemental material with massless Dirac fermions. The buckling and coupling between the two sublattices not only enhance the energetic stability, but also are the key factors for the emergence of the distorted Dirac cone.

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“…An even more stable modification of β-boron has been proposed with 106 atoms in the unit cell 5 . Boron based nanostructures have also been proposed 6 , and boron single and double wall nanotubes and boron nanoribbons have been reported [7][8][9] .…”

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confidence: 99%

Behavior of hydrogen ions, atoms, and molecules inα-boron studied using density functional calculations

et al. 2011

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For full reference please see: Phys. Rev. B 83, 024101, 2011 We examine the behaviour of hydrogen ions, atoms and molecules in α-boron using density functional calculations. Hydrogen behaves as a negative-U centre, with positive H ions preferring to sit off-center on inter-layer bonds and negative H ions sitting preferably at in-plane sites between three B12 icosahedra. Hydrogen atoms inside B12 icosahedral cages are unstable, drifting off-center and leaving the cage with only a 0.09 eV barrier. While H 0 is extremely mobile (diffusion barrier 0.25 eV), H + and H − have higher diffusion barriers of 0.9 eV. Once mobile these defects will combine, forming H2 in the interstitial void space, which will remain trapped in the lattice until high temperatures. Based on these results we discuss potential differences for hydrogen behaviour in β-boron, and compare with experimental muon-implantation data.PACS numbers: 61.72. Cc,71.15.Mb,88.85.mh,13.35.Bv Boron is a fascinating elemental material about which we are still making many new discoveries. Only recently a new form of Boron was found, showing unusual negative-U behaviour between B 12 and B 2 sub-units within the crystal 1 . Sitting somewhere between metals and insulators on the periodic table, the bonding in boron is strongly dependent on local environment and factors such as temperature, pressure and impurities. The simplest such impurity is hydrogen, yet to date no studies exist of the behaviour of hydrogen in bulk boron.To date 16 allotropes of elemental boron have been reported. The best known crystal phases are the α-rhombohedral structure (α-boron) and the β-rhombohedral structure (β-boron), as well as two tetragonal modifications which are probably stabilized by foreign atoms 2 . The α-boron structure as the simplest of them contains 12 atoms in a rhombohedral unit cell forming a slightly distorted icosahedron (B 12 , see Figure 2). More complex, but thermodynamically stable at high temperatures is the β-boron crystal with a unit cell containing 105 atoms 3 . Compared with the α-boron phase, β-boron bulk is less dense and softer4 . An even more stable modification of β-boron has been proposed with 106 atoms in the unit cell 5 . Boron based nanostructures have also been proposed 6 , and boron single and double wall nanotubes and boron nanoribbons have been reported 7-9 .Boron compounds have been proposed as promising candidates for hydrogen-storage 10 , for example alkali doped boron sheets as possible hydrogen acceptors 11 . Although such applied studies are already underway, there still remains much to understand concerning hydrogen behaviour in the crystalline boron phases, which forms the subject of the current article. Given that the B 12 -icosahedron is the basic element for both rhombohedral modifications, we have focused on the simpler α-boron phase. Based on these results comparable sites for the β-boron phase are discussed. I. COMPUTATIONAL DETAILSWe perform density functional theory calculations under the local density approximation as implem...

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Free standing double walled boron nanotubes

Cited by 18 publications

References 40 publications

Novel spherical boron clusters and structural transition from 2D quasi-planar structures to 3D double-rings

Novel spherical boron clusters and structural transition from 2D quasi-planar structures to 3D double-rings

Semimetallic Two-Dimensional Boron Allotrope with Massless Dirac Fermions

Behavior of hydrogen ions, atoms, and molecules inα-boron studied using density functional calculations

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