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We utilize a combined computational-experimental approach to examine the influence of indium nanoparticle (NP) array distributions on deep-ultraviolet (UV) plasmon resonances. For photon energies < 5.7 eV, analysis of ellipsometric spectra reveals an increase in silicon reflectance induced by indium NP arrays on silicon. For various energies in the range 5.7–7.0 eV, a decrease in reflectance is induced by the NP arrays. Similar trends in reflectance are predicted from finite-difference time-domain (FDTD) simulations using NP size distributions extracted from atomic-force micrographs as input. In addition, in the energy range of 7.4–9.2 eV, the FDTD simulations reveal reflectance minima, characteristic of localized surface plasmon resonances. Electron energy-loss spectroscopy collected from individual indium NPs reveals the presence of LSPR at ≈ 8 eV, further supporting the promise of indium NP arrays on silicon for deep-UV plasmonics. 

Abstract It has been suggested that Ba₃In₂O₆might be a high-T_csuperconductor. Experimental investigation of the properties of Ba₃In₂O₆was long inhibited by its instability in air. Recently epitaxial Ba₃In₂O₆with a protective capping layer was demonstrated, which finally allows its electronic characterization. The optical bandgap of Ba₃In₂O₆is determined to be 2.99 eV in-the (001) plane and 2.83 eV along thec-axis direction by spectroscopic ellipsometry. First-principles calculations were carried out, yielding a result in good agreement with the experimental value. Various dopants were explored to induce (super-)conductivity in this otherwise insulating material. NeitherA- norB-site doping proved successful. The underlying reason is predominately the formation of oxygen interstitials as revealed by scanning transmission electron microscopy and first-principles calculations. Additional efforts to induce superconductivity were investigated, including surface alkali doping, optical pumping, and hydrogen reduction. To probe liquid-ion gating, Ba₃In₂O₆was successfully grown epitaxially on an epitaxial SrRuO₃bottom electrode. So far none of these efforts induced superconductivity in Ba₃In₂O_6,leaving the answer to the initial question of whether Ba₃In₂O₆is a high-T_csuperconductor to be ‘no’ thus far.