Publications by authors named "Arta Sadrzadeh"

Traditional inductors in modern electronics consume excessive areas in the integrated circuits. Carbon nanostructures can offer efficient alternatives if the recognized high electrical conductivity of graphene can be properly organized in space to yield a current-generated magnetic field that is both strong and confined. Here we report on an extraordinary inductor nanostructure naturally occurring as a screw dislocation in graphitic carbons.

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The structural stability and diversity of elemental boron layers are evaluated by treating them as pseudoalloy B(1-x)[hexagon](x), where [hexagon] is a vacancy in the close-packed triangular B lattice. This approach allows for an elegant use of the cluster expansion method in combination with first-principles density-functional theory calculations, leading to a thorough exploration of the configurational space. A finite range of compositions x is found where the ground-state energy is essentially independent of x, uncovering a variety of stable B-layer phases (all metallic) and suggesting polymorphism, in stark contrast to graphene or hexagonal BN.

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Using first principles calculations, we show the high hydrogen storage capacity of metallacarboranes, where the transition metal (TM) atoms can bind up to 5 H(2)-molecules. The average binding energy of ∼0.3 eV/H favorably lies within the reversible adsorption range.

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Using ab initio calculations, we analyze electronic structure and vibrational modes of the boron fullerene B(80), a stable, spherical cage similar in shape to the well-known C(60). There exist several isomers, lying close in structure and energy, with total energy difference within approximately 30 meV. We present detailed analysis of their electronic structure and geometry.

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We investigate the properties of nanotubes obtained from recently described boron alpha-sheet, using density functional theory. Computations confirm their high stability and identify mechanical stiffness parameters. This allows one to further analyze the basic vibrations, including the radial breathing mode Raman frequency, fRBM = 210(nm/ d) cm (-1).

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The geometry, electronic, and structural properties of an unusually stable boron cage made of 80 boron atoms are studied, using ab initio calculations. The shape of this cluster is very similar to that of the well-known C60 fullerene, but in the B80 case, there is an additional atom in the center of each hexagon. The resulting cage preserves the Ih symmetry, has a relatively large highest occupied and lowest unoccupied energy gap ( approximately 1 eV) and, most importantly, is energetically more stable than boron double rings, which were detected in experiments and considered as building blocks of boron nanotubes.

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