D.M. Chen

Optical enhancement brought by doping Gd(3+) ions into Ce: YAG ceramics for indoor white light-emitting diodes.

We dope Gd(3+) ions into Ce: YAG ceramics to induce red-shift in the photoluminescence, of which the degree is proportional to the Gd(3+) doping concentration. This kind of ceramic, when collaborating with InGaN blue chips, proves to be a promising fluorescent material of white light-emitting diodes, for not only its high in-line transmittance and decent quantum yield, but also the improvement in color rendering ability brought by the red-shift, which enhances the ratio of red portion in spectra. We demonstrate that 10% is the optimized value of Gd(3+) doping concentration, as it provides the maximum color rendering index of ~78 with luminous efficiency as high as 128 lm/W.

New phase transition in Na

We performed a Raman scattering study of Na

_{2}

_2

Ti

Ti

_{2}

_2

As

As

_{2}

_2

O revealed by Raman scattering

O. We identified a symmetry breaking structural transition at around

Raman scattering investigation of the quasi-one-dimensional superconductor Ta4Pd3Te16

T_s = 150

Robustness of topological states with respect to lattice instability in the nonsymmorphic topological insulator KHgSb

K, which matches a large bump in the electrical resistivity. Several new peaks are detected below that transition. Combined with first-principles calculations, our polarization-dependent measurements suggest a charge instability driven lattice distortion along one of the Ti-O bonds that breaks the 4-fold symmetry and more than doubles the unit cell.