Simulation and Optimization of δ-doped AlInAs/InGaAs HEMT for High Frequency Applications Farhan Aziz, M.J. Siddiqui Department of Electronics and Communication Engg. BSACET, Mathura, U.P., India Department of Electronics Engg. Zakir Husain College of Engg. and Technology Aligarh Muslim University, Aligarh, U.P., India ____________________________________________________________________________...

A simple two-band model is suggested explaining recently reported unusual features for hopping magnetoresistance and the metal-insulator transition in 2D structures. The model implies that the conductivity is dominated by the upper Hubbard band (D-band). Experimental studies of hopping magnetoresistance for Si δ-doped GaAs/AlGaAs heterostructure give additional evidences for the model.

We explain the anomalous doping dependence of zone boundary (π, 0) and (π, π) bond-stretching phonons in La2−δSrδCuO4 in the range 0 < δ < 0.35. Our calculations are based on a theory for the density response of doped Mott-Hubbard insulators.

The kinetics of CO2 reduction over nonstoichimetric ceria, CeO2-δ, a material of high potential for thermochemical conversion of sunlight to fuel, has been investigated for a wide range of nonstoichiometries (0.02 ≤ δ ≤ 0.25), temperatures (693 ≤ T ≤ 1273 K), and CO2 concentrations (0.005 ≤ pCO2 ≤ 0.4 atm). Samples were reduced thermally at 1773 K to probe low nonstoichiometries (δ < 0.05) and ...