Graphyne Nanotubes Research Articles

Study of the Influence of Transition Metal Atoms on Electronic and Magnetic Properties of Graphyne Nanotubes Using Density Functional Theory

Density functional theory calculations were used to study the adsorption of three transition metal atoms (Fe, Co, and Ni) on the external surface of two zigzag and two armchair graphyne nanotubes. The most stable position for the adsorption of all three metal atoms on all nanotubes is on the acetylenic ring. The metal atom remains in the plane of the acetylenic ring and makes six bonds with neighboring carbon atoms. Fe and Co complexes are magnetic and show different properties such as metal, semimetal, half-semimetal, and half-semiconductor. Ni complexes are nonmagnetic and semiconductive, with a narrower bandgap in comparison to bare tubes. The results of these calculations are relevant for spintronics and the design of future electronic devices.

On the quantum graph spectra of graphyne nanotubes

We describe explicitly the dispersion relations and spectra of periodic Schrodinger operators on a graphyne nanotube structure.

Thermoelectric Transport in Graphyne Nanotubes

The thermoelectric transport properties of graphyne nanotubes (GNTs) are investigated by using the nonequilibrium Green’s function (NEGF) method, as implemented in the density functional based tigh...

Calcium-decorated graphyne nanotubes as promising hydrogen storage media: A first-principles study

First principles calculations based on density functional theory are carried out to study the hydrogen storage properties of Ca-decorated graphyne nanotubes. The results show that Ca atoms can be adsorbed stably on the acetylenic ring of the graphyne nanotube (GNT) without Ca atom clustering. Both the polar interactions and the orbital hybridizations contribute to the adsorption of H2 molecules. The average adsorption energy is in the range of 0.13–0.33eV/H2 which is almost independent of the tube diameter. Each Ca atom can adsorb up to four H2 molecules due to the steric hindrance of the H2 molecules. With a hydrogen uptake of 7.44–8.96wt%, the Ca-decorated GNT is an optimal choice for hydrogen recycling at near ambient conditions.

Theoretical investigation of electromechanical effects for graphyne carbon nanotubes.

We present a theoretical study of the electronic and mechanical properties of graphyne-based nanotubes (GNTs). These semiconducting nanotubes result from the elongation of one-third of the covalent interconnections of graphite-based nanotubes by the introduction of yne groups. The effect of charge injection on the dimensions of GNTs was investigated using tight-binding calculations. Low amounts of electron injection are predicted to cause qualitatively different responses for armchair and zigzag graphyne nanotubes. Although the behavior is qualitatively similar to the usual carbon nanotubes, the charge-induced strains are predicted to be smaller for the GNTs than for ordinary single walled carbon nanotubes.

New families of carbon nanotubes based on graphyne motifs

Electronic properties of proposed new families of carbon single walled nanotubes areinvestigated. These nanotubes, called graphynes, result from the elongation of covalentinterconnections of graphite-based nanotubes by the introduction of yne groups. Analogousto ordinary nanotubes, armchair, zigzag and chiral graphyne nanotubes are possible.Tight-binding and ab initio density functional methods were used to predict theelectronic properties of these unusual nanotubes. Of the three graphyne nanotubefamilies analysed here, two provide metallic behaviour for armchair tubes andeither metallic or semiconducting behaviour for zigzag nanotubes. For the othergraphyne nanotube family investigated a diameter and chirality independentbandgap is predicted and a bandgap modulation study by structural distortions hasbeen carried out for small longitudinal tube deformations. Interestingly, while thebandgap is insensitive to structure, the stress-induced bandgap changes can stronglydepend both on the nanotube type and whether the strain is tensile or compressive.

Families of carbon nanotubes: Graphyne-based nanotubes

New families of carbon single-walled nanotubes are proposed and their electronic structures are investigated. These nanotubes, called graphynes, result from the elongation of covalent interconnections of graphite-based nanotubes by the introduction of yne groups. Analogously to ordinary nanotubes, armchair, zigzag, and chiral graphyne nanotubes are possible. We here predict the electronic properties of these unusual nanotubes using tight-binding and ab initio density functional methods. Of the three graphyne nanotube families analyzed here, two provide metallic behavior for armchair tubes and either metallic or semiconducting behavior for zigzag nanotubes. A diameter- and chirality-independent band gap is predicted for the other investigated graphyne family, as well as an oscillatory dependence of the effective mass on nanotube diameter.

Graphyne nanotubes: New Families of Carbon Nanotubes

ABSTRACTFundamentally new families of carbon single walled nanotubes are proposed. These nanotubes, called graphynes, result from the elongation of covalent interconnections of graphite-based nanotubes by the introduction of yne groups. Similarly to ordinary nanotubes, armchair, zig-zag, and chiral graphyne nanotubes are possible. We present here results for the electronic properties of graphyne based tubes obtained from tight-binding and ab initio density functional methods.