Complementary angle-resolved photoemission and bulk-sensitive k-resolved resonant inelastic x-ray scattering of divalent hexaborides reveal a >1 eV X-point gap between the valence and conduction bands, in contradiction to the band overlap assumed in several models of their novel ferromagnetism. This semiconducting gap implies that carriers detected in transport measurements arise from defects, ...

The electronic structures of BiOX (X = F, Cl, Br, I) photocatalysts have been calculated with and without Bi 5d states using the experimental lattice parameters, via the plane-wave pseudopotential method based on density functional theory (DFT). BiOF exhibits a direct band gap of 3.22 or 3.12 eV corresponding to the adoption of Bi 5d states or not. The indirect band gaps of BiOCl, BiOBr, and Bi...

When graphite is doped with electrons, carbon-carbon bonds lengthen and Raman-active phonons soften as antibonding states fill. However, in semiconducting carbon nanotubes, one Raman-active G-band mode increases in frequency at low doping levels. We show how phase constraints on the conduction-band wave function expose a latent bonding character in the conduction band of certain nanotubes. In t...

Experiments on intense laser driven dielectrics have revealed population transfer to the conduction band to be oscillatory in time. This is in stark contrast to ionization in semiconductors and is currently unexplained. Current ionization theories neglect coupling between the valence and conduction band and therewith, the dynamic Stark shift. Our single-particle analysis identifies this as a po...

A detailed study on the mechanism of band-to-band tunneling in carbon nanotube field-effect transistors (CNFETs) is presented. Through a dual-gated CNFET structure tunneling currents from the valence into the conduction band and vice versa can be enabled or disabled by changing the gate potential. Different from a conventional device where the Fermi distribution ultimately limits the gate volta...

We calculate the {\em exact} time-resolved ARPES spectrum of a two-band model semiconductor driven out equilibrium by resonant and nonresonant laser pulses, highlighting effects phonon-induced decoherence relaxation. Resonant} excitations initially yield replica valence} band shifted upward energy exciton peak in photoabsorption. This phase is eventually destroyed decoherence: valence-band lowe...

A detailed model for the electronic properties of self-assembled InAs/GaAs quantum dots (SADs) is presented, with emphasis on inter-level transitions and many-body effects. The model is based on the self-consistent solution of three-dimensional Poisson and Schrödinger equations within the local (spin-) density approximation. Nonparabolicity of the band structure and a continuum model for the st...

A two-band k·p model for the conduction band of silicon is proposed and compared with other band structure models, notably the nonlocal empirical pseudo-potential method and the spds nearest-neighbor tight-binding model. The twoband k·p model is demonstrated to predict results consistent with the empirical pseudo-potential method, and to accurately describe the band structure around the valley ...