We report, for the first time, about an intermediate band solar cell implemented with InAs/AlGaAs quantum dots whose photoresponse expands from 250 to ∼6000  nm. To our knowledge, this is the broadest quantum efficiency reported to date for a solar cell and demonstrates that the intermediate band solar cell is capable of producing photocurrent when illuminated with photons whose energy equals t...

The electron subband structure in a thin (100) silicon film is analyzed based on a two-band k·p theory. For unprimed subbands the dependence of the nonparabolicity parameter on film thickness is obtained. The two-band k·p theory gives a thickness dependence of the effective masses for primed subbands. Limitations of the model are discussed. The importance of the nonparabolicity parameter depend...

In the context of the dynamical mean-field theory (DMFT) of the Hubbard model, we study the behavior of the compressibility near the density driven Mott transition at finite temperatures. We demonstrate this divergence using DMFT and quantum Monte Carlo simulations in the one-band and the two-band Hubbard model. We supplement this result with considerations based on the Landau theory framework,...

We describe the reduction from four to two dimensions of the SU(2) Donaldson-Witten theory and the dual twisted Seiberg-Witten theory, i.e. the Abelian topological field theory corresponding to the Seiberg–Witten monopole equations. NBI-HE-96-14 hep-th/9603023 ∗E-mail: [email protected]

Nonlinear systems usually have complicated output frequencies in the frequency domain. For the class of nonlinear Volterra systems, some interesting properties for system output frequencies are studied in this paper. These properties provide a novel insight into the output frequencies of Volterra systems, i.e., the periodicity of the output frequencies. They also demonstrate several novel frequ...

We studied coherent backscattering (CBS) of light from opal photonic crystals with incomplete band gaps. We observed a dramatic broadening of the CBS cone for incident angles close to the Bragg condition in the crystals. We modify the conventional CBS theory to incorporate Bragg attenuation resulting from the photonic band structure. By fitting the CBS data with the modified theory, we extract ...

We show that the results of photoemission and inverse photoemission experiments on bulk copper can be quantitatively described within band-structure theory, with no evidence of effects beyond the single-quasiparticle approximation. The well-known discrepancies between the experimental band structure and the Kohn-Sham eigenvalues of density functional theory are almost completely corrected by se...

in this paper, a photonic crystal waveguide with point defects and lattice constant perturbations of +5%, -5% are being investigated. firstly waveguide structures with constant and specific parameters are being studied and photonic band gap diagrams for te/tm modes are depicted; then pulse propagation in the frequencies available in the band gap are shown. after that, effects of parameters like...

We present an efficient two-band k·p theory which accurately describes the six lowest conduction band valleys in silicon. By comparing the model with full band pseudo-potential calculations we demonstrate that the model captures both the nonparabolicty effects and the stress-induced band structure modification for general stress conditions. It reproduces the stress dependence of the effective m...