Approaching bulk limit for three-dimensional solids via the cyclic cluster approximation: Semiempirical INDO study

Noga, Jozef; ack, Pavol Ba; Biskupi, Stanislav; a, Roman Bo; Pelikn, Peter; ek, Michal Svr; Zajac, Anton

doi:10.1002/(sici)1096-987x(19990130)20:2<253::aid-jcc7>3.0.co;2-9

Cited by 32 publications

(13 citation statements)

References 30 publications

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“…c. Both applied methods (DFT and CC HF–SCF —Section 2.1) show that a slab with 25 layers approaches the stability of bulk MgB 2 . As the numbers of layers increases, the stability of the slab approaches the bulk limit and the electronic BS of the slab evolves toward the BS topology of bulk MgB 2 .…”

Section: Resultsmentioning

confidence: 99%

“…Electronic structure calculations on the relaxed geometries of bulk MgB 2 and slabs were performed using DFT‐band version of the Amsterdam Density Functional (ADF) program package in the LDA and GGA‐PBE approximations with a triple‐ζ Slater‐type basis set with polarization function (TZP) from the ADF basis set library and the Cyclic Cluster HF–SCF (CC HF–SCF) method with the INDO Hamiltonian. The BS topologies of the studied bulk and slab structures obtained by these methods are equivalent.…”

Section: Calculation Methodsmentioning

confidence: 99%

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Large diameter multiwall nanotubes of MgB₂: Structural aspects and stability of superconducting nanotubular magnesium boride

Baňacký

Noga

Szöcs

et al. 2015

Physica Status Solidi (b)

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Based on a theoretical study, we demonstrated that magnesium boride nanotubes can reach the same stability as bulk MgB 2 structure. However, most stable nanotubular forms are not structurally derived from mixed triangular-hexagonal structural motifs of a single layer sheet, which is thought to be the 2D precursor form of all boron nanotubes. MgB 2 multiwall nanotubular structures that are derived from multilayer MgB 2 slabs with honeycomb Bnetworks in hexagonal lattices are more stable. The results of an ab initio study of multilayer slabs of MgB 2 show that a 25-layer slab approaches the stability of bulk MgB 2 . The critical parameter of the corresponding multiwall nanotubes is the inner diameter; the calculated value is ~ 32.6nm, which is independent of the number of walls. The outer diameters of 25-wall nanotubes are ~ 51 nm, and terminal Mg atoms are located on the outer surfaces of the nanotubes. The electronic band structures of MgB 2 -multiwall nanotubes (MgB 2 MWNT) correspond to the band structure character and topology of superconducting bulk MgB 2 . The results confirm that the quasi-1D superconductor MgB 2 MWNT is a stable structure and can be synthesized.

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Section: Resultsmentioning

confidence: 99%

Section: Calculation Methodsmentioning

confidence: 99%

Large diameter multiwall nanotubes of MgB₂: Structural aspects and stability of superconducting nanotubular magnesium boride

Baňacký

Noga

Szöcs

et al. 2015

Physica Status Solidi (b)

Self Cite

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“…That means that the interaction of basis function µ , which is centered on the real atom M , with basis function σ , which is centered at atom P , is replaced by the interaction with the closer translationally equivalent basis function

σ^{-}

centered on the virtual atom P − . In contrast to previous implementations, which do not use WSSCs, it is not necessary, that the cluster contains an inversion center.…”

Section: Theorymentioning

confidence: 97%

The cyclic cluster model at hartree–fock level

Peintinger

Bredow

2014

J Comput Chem

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We present the implementation of the cyclic cluster model (CCM) formalism at the Hartree-Fock (HF) level. In contrast to other periodic models, the CCM is a Γ-point approach. Integration is carried out in real space within a finite interaction area determined by the size and the shape of the cluster that corresponds to a supercell of the solid, surface, or polymer. Particular care has to be taken for the proper treatment of three- and four-center integrals that involve basis functions located at the boundaries of the Wigner-Seitz supercell, which defines the interaction region. The similarity between the CCM formalism and molecular approaches allows in principle the application of sophisticated post HF methods to solid-state problems with only moderate modification of the molecular code. We show for selected model systems, that with our approach, the electronic structure and energetics obtained by the conventional supercell model is fully reproduced.

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“…The full set BS for allowed values of rotation wave numbers r = 0,±1,…,±11 of studied SWBNTs is presented in SD1-2. The BS calculations were performed using cyclic cluster approach at semiempirical INDO level [29] employing the helical symmetry as described in the Section 2.1.…”

Section: Acknowledgementsmentioning

confidence: 99%

Toward possibility of high-temperature bipolaronic superconductivity in boron tubular polymorph: Theoretical aspects of transition into anti-adiabatic state

Baňacký

Noga

Szöcs

2012

Journal of Physics and Chemistry of Solids

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Abstract. Large diameter single-wall boron nanotubes (SWBNT) produced by 2%Mg-mesoporous Al 2 O 3 catalysis show diamagnetic transition at ~ 40 K and ~ 80 K, which is a serious indication for possible superconductivity (J.Phys.Chem.C113, (2009) 17661). Theoretical study which explains or disproves possibility of superconductivity in boron is so far absent, however. Here we apply first-principles formulation of nonadiabatic theory of electron-vibration interactions in study of band structure of boron nanotubes. The ab initio results show that electron-vibration coupling induces in SWBNT with diameter larger than 15 Å transition into anti-adiabatic ground state at distorted-fluxional geometry. Thermodynamic and magnetic properties of anti-adiabatic ground state imply possibility of bipolaronic superconductivity. Calculated critical temperature T c of large diameter SWBNT is 39 K and inclusion of Mg into a tube increases T c up to 70-90 K. Presence of Al in SWBNT suppress superconductivity and a tube remains metallic down to 0 K. Superconducting properties could established boron nanotubes superior material for nanotechnology.

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Approaching bulk limit for three-dimensional solids via the cyclic cluster approximation: Semiempirical INDO study

Cited by 32 publications

References 30 publications

Large diameter multiwall nanotubes of MgB₂: Structural aspects and stability of superconducting nanotubular magnesium boride

Large diameter multiwall nanotubes of MgB₂: Structural aspects and stability of superconducting nanotubular magnesium boride

The cyclic cluster model at hartree–fock level

Toward possibility of high-temperature bipolaronic superconductivity in boron tubular polymorph: Theoretical aspects of transition into anti-adiabatic state

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Approaching bulk limit for three-dimensional solids via the cyclic cluster approximation: Semiempirical INDO study

Cited by 32 publications

References 30 publications

Large diameter multiwall nanotubes of MgB2: Structural aspects and stability of superconducting nanotubular magnesium boride

Large diameter multiwall nanotubes of MgB2: Structural aspects and stability of superconducting nanotubular magnesium boride

The cyclic cluster model at hartree–fock level

Toward possibility of high-temperature bipolaronic superconductivity in boron tubular polymorph: Theoretical aspects of transition into anti-adiabatic state

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Product

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Large diameter multiwall nanotubes of MgB₂: Structural aspects and stability of superconducting nanotubular magnesium boride

Large diameter multiwall nanotubes of MgB₂: Structural aspects and stability of superconducting nanotubular magnesium boride