Search

The electronic and optical properties of Cu2ZnSiS4, Cu2ZnSiSe4 and Cu2ZnSiTe4 in kesterite and stannite structures are systematically studied using first-principles calculations. Crystal field splitting, optical transitions, p-d bonding, and anti-bonding overlapping are analyzed. The physical and chemical trends in these properties are investigated with respect to the crystal structure and anion atomic number. The optical spectra, such as dielectric function, refractive index, reflectivity and absorption coefficient are explored in a broad range of energy. A good agreement between the calculated results and experimental data is obtained. [ABSTRACT FROM AUTHOR]

The unprecedented applications of two-dimensional (2D) atomic sheets in spintronics are formidably hindered by the lack of ordered spin structures. Here we present first-principles calculations demonstrating that the recently synthesized dimethylmethylene-bridged triphenylamine (DTPA) porous sheet is a ferromagnetic half-metal and that the size of the band gap in the semiconducting channel is roughly 1 eV, which makes the DTPA sheet an ideal candidate for a spin-selective conductor. In addition, the robust half-metallicity of the 2D DTPA sheet under external strain increases the possibility of applications in nanoelectric devices. In view of the most recent experimental progress on controlled synthesis, organic porous sheets pave a practical way to achieve new spintronics. [ABSTRACT FROM AUTHOR]