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We investigate the superconducting order parameter, the spectral and optical properties in a stripe model with spin-(charge-) domain-derived scattering potential V(s) (V(c)). We show that the charge-domain-derived scattering is less effective than the spin scattering on the suppression of superconductivity. For [Formula: see text], the spectral weight concentrates on the (π,0) antinodal region and a finite energy peak appears in the optical conductivity with the disappearance of the Drude peak. But for V(s)≈V(c), the spectral weight concentrates on the (π/2,π/2) nodal region and a residual Drude peak exists in the optical conductivity without the finite energy peak. These results consistently account for the divergent observations in the ARPES and optical conductivity experiments in several high- T(c) cuprates and suggest that the 'insulating' and 'metallic' properties are intrinsic to the stripe state, depending on the relative strength of the spin- and charge-domain-derived scattering potentials.

The characteristics of blue InGaN light emitting diodes with AlGaN/InGaN superlattice barriers are investigated. The efficiency droop can be improved when AlGaN/InGaN superlattice barriers are used. This improvement can be attributed to the reduced polarization effect in the active region by using AlGaN/InGaN superlattice barriers.

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In the framework of the slave-boson approach to the t-t'-t''-J model, it is found that for electron-doped high- T(c) cuprates, the staggered antiferromagnetic (AF) order coexists with the superconducting (SC) order in a wide doping level ranged from underdoped to nearly optimally doped at the mean-field level. In the coexisting phase, it is revealed that the spin response is commensurate in a substantial frequency range below a crossover frequency ω(c) for all dopings considered, and it switches to the incommensurate structure when the frequency is higher than ω(c). This result is in agreement with the experimental measurements. Comparison of the spin response between the coexisting phase and the pure SC phase with a d(x(2)-y(2))-wave pairing plus a higher harmonics term (DP+HH) suggests that the inclusion of the two-band effect is important to consistently account for both the dispersion of the spin response and the non-monotonic gap behavior in the electron-doped cuprates.