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In this article, a resolution of 15 × 30 blue flip-chip micro-LED array with a pixel size of 20 × 35 μm2 was fabricated. The micro-LED array was hybridized with the silicon backplane via flip-chip bonding technology and liftoff process. The Au/In/Au multilayers could provide lower electrical resistivity and reduce cracks and voids at the film interface, leading to a micro-LED display that had uniform brightness and high reliability. The blue micro-LED display exhibits excellent optical and electrical characteristics, including a low turn-on voltage of 2.8 V and a brightness reach of 1.78 × 107 cd/m2 (nits) at 5 V. Additionally, there appears in the emission spectrum at a voltage of 3 V a blue shift of a peak wavelength from 455.51 to 453.96 nm. Further, the average shear strength of the micro-LED bonded by Au/In/Au multilayers increased to 2.24 g. The presented method has tremendous potential in high resolution micro-LED displays for augmented and virtual reality devices. [ABSTRACT FROM AUTHOR]

We report an inelastic neutron scattering study of candidate multiferroic ErFeO 3 , a compound that has been previously reported to have three different magnetic states and undergoes signatures of Fe 3 + − Er 3 + cooperative coupling. The spectrum at low energy transfer is dominated by excitations of the Er 3 + character, even above the Er 3 + antiferromagnetic ordering temperature of 4.5 K. In addition, a crystalline electric field excitation at 6 meV exhibits additional energy splitting upon cooling through 4.5 K with mode-dependent polarization. This indicates different moment directions for these modes, an interesting consequence of C y ordering of the Er 3 + moments. [ABSTRACT FROM AUTHOR]

We report electrical and thermal transport properties of Mn-based material BaMn2Bi2 with ThCr2Si2 structure. The resistivity of the antiferromagnetic BaMn2Bi2 shows a metal-semiconductor transition at ∼80 K with decreasing temperature. Correspondingly, the thermopower S shows a peak at the same temperature, approaching 150 μV/K. With increasing temperature, S decreases to about 125 μV/K at the room temperature. The magnetic field enhances the peak value to 210 μV/K. The Hall resistivity reveals an abrupt change of the carrier density close to the metal-semiconductor transition temperature. [ABSTRACT FROM AUTHOR]

We report temperature and magnetic field dependence of the thermal transport properties in single crystals of (Sr/Ca)MnBi2 with linear energy dispersion. In SrMnBi2 thermopower is positive, indicating hole-type carriers and the magnetic field enhances the thermopower significantly. The maximum change of thermopower is about 1600% in 9 T field and at 10 K. A negative thermopower is observed in CaMnBi2 with dominant electron-type carriers, and, in contrast, the magnetic field suppresses the absolute value of thermopower. First-principle band structure shows that the chemical potential is close to the Dirac-cone-like points in linear bands. The magnetic field suppresses the apparent Hall carrier density of CaMnBi2 below 50 K. The large magnetothermopower effect in (Sr/Ca)MnBi2 is attributed to the magnetic field shift of chemical potential. [ABSTRACT FROM AUTHOR]

Kondo insulator FeSb2 with large Seebeck coefficient would have potential in thermoelectric applications in cryogenic temperature range if it had not been for large thermal conductivity κ. Here we studied the influence of different chemical substitutions at Fe and Sb site on thermal conductivity and thermoelectric effect in high quality single crystals. At 5% of Te doping at Sb site, thermal conductivity is suppressed from ∼250 W/Km in undoped sample to about 8 W/Km. However, Cr and Co doping at Fe site suppresses thermal conductivity more slowly than Te doping, and even at 20% Cr/Co doping the thermal conductivity remains ∼30 W/Km. The analysis of different contributions to phonon scattering indicates that the giant suppression of κ with Te is due to the enhanced point defect scattering originating from the strain field fluctuations. In contrast, Te-doping has small influence on the correlation effects and then for small Te substitution the large magnitude of the Seebeck coefficient is still preserved, leading to the enhanced thermoelectric figure of merit (ZT ∼0.05 at ∼100 K) in Fe(Sb0.9Te0.1)2. [ABSTRACT FROM AUTHOR]

The electric field dependence on the dielectric properties of the porous ceramics was studied theoretically. The dielectric constant of the porous ceramics under certain direct current (dc) bias field and the real strength electric field in the porous ceramics were given quantitatively. As the pore can share the electric field, the tunability of the porous ceramics will be decreased when the porosity increases. The dielectric constant evolution of Ba0.6Sr0.4TiO3-based porous ceramics with the dc bias electric field can be successfully explained by our theoretical results. Taking Ba0.6Sr0.4TiO3-based porous ceramic samples, for example, there is good correspondence between the theoretical and the experimental results. [ABSTRACT FROM AUTHOR]

We report the large linear magnetoresistance (∼300% in 9 T field at 2 K) and magnetothermopower in layered SrZnSb2 crystal with quasi-two-dimensional Sb layers. A crossover from the semiclassical parabolic field dependent magnetoresistance to linear field dependent magnetoresistance with increasing magnetic field is observed. The magnetoresistance behavior can be described very well by combining the semiclassical cyclotron contribution and the quantum limit magnetoresistance. Magnetic field also enhances the thermopower. Our results can be well understood by the magnetotransport of Dirac states in the bulk band structure. [ABSTRACT FROM AUTHOR]