No abstract

The generalized gradient approximation (GGA) for the exchange-correlation energy has recently become available in a simple form that can be used in place of the local density approximation (LDA). We have applied this simplified GGA within a self-consistent LMTO method to study the equilibrium volume and bulk moduli of 3d and 4d transition metals. We have obtained systematic improvements of the results in comparison with those obtained using the LDA.

A systematic study of geometrical structures and electrical properties of CdS nanotubes is carried out within the density functional formalism. Geometrical and electrical properties such as wall thickness, curvature, stability, bandgap energies, work functions and charge redistribution analysis are done for CdS nanotubes with varied diameter for understanding their character. It is found that all the tubes remain hollow even after complete relaxation and their work function, bandgap as well as wall thickness decreases with increasing diameter. Some of these findings are in agreement with experimental observation that thermionic emission enhances with decreasing wall thickness of CdS nanotubes.

No abstract

We report structural and electrical properties such as wall thickness, binding energy, curvature energy, band‐gap energy, work function etc. of various zigzag CdS nanotubes within the framework of density functional theory. Binding energy calculation reveals that all the nanotubes studied here are stable and they follow classical elasticity law. The wall thickness, band‐gap, and work function of the tubes are found to decrease with increasing tube diameter. Quantitatively, the band‐gap may be tuned from 1.711 to 2.162 eV and from 0.871 to 1.291 eV, respectively, while the work function may be varied from 6.081 to 6.239 eV and from 4.679 to 4.911 eV, respectively, by changing parameters such as diameter and atomic arrangement of the tubes. The results may be useful in designing various nanoscale devices.