Comparative study of adsorptions, reactions and electronic properties of U atoms on Cu(111), Ag(111), Au(111) and Ru(0001) surfaces.

The mysterious properties of individual U atoms on transition metal surfaces play indispensable parts in supplementing our understanding of uranium-transition metal systems, which are important subjects for both nuclear energy applications and fundamental scientific studies. By using scanning tunneling microscopy and density functional theory calculations, the adsorptions, reactions and electronic properties of individual U atoms on Cu(111), Ag(111), Au(111) and Ru(0001) surfaces were comparatively studied for the first time in this work. Upon the deposition of a small amount of U onto Cu(111) or Ag(111) at 8 K, individual U atoms show relatively high activity and can either be adsorbed on intact substrate surfaces or induce various surface vacancies surrounded by clusters of substrate atoms.

Electronic structure and photoabsorption of Ti ions in reduced anatase and rutile TiO.

We have used two-photon photoemission (2PPE) spectroscopy and first-principles density functional theory calculations to investigate the electronic structure and photoabsorption of the reduced anatase TiO2(101) and rutile TiO2(110) surfaces. 2PPE measurements on anatase (101) show an excited resonance induced by reduced Ti3+ species centered around 2.5 eV above the Fermi level (EF).

Physical properties and field-induced metamagnetic transitions in UAuSb.

We have successfully synthesized single crystals of UAuSb using a flux method and present a comprehensive study of its physical properties by measuring the magnetic susceptibility, electrical resistivity and specific heat. Evidence for at least three magnetic phases is observed in the field-temperature phase diagram of UAuSb. In zero field, the system undergoes an antiferromagnetic transition at 71 K, and upon further cooling it passes through another antiferromagnetic phase with a ferromagnetic component, before reaching a ferromagnetic ground state.

Observation and Manipulation of Visible Edge Plasmons in BiTe Nanoplates.

Noble metals, like Ag and Au, are the most intensively studied plasmonic materials in the visible range. Plasmons in semiconductors, however, are usually believed to be in the infrared wavelength region due to the intrinsic low carrier concentrations. Herein, we observe the edge plasmon modes of BiTe, a narrow-band gap semiconductor, in the visible spectral range using photoemission electron microscopy (PEEM).

Photocatalytic chemistry of methanol on rutile TiO₂(011)-(2 × 1).

Photocatalytic chemistry of methanol on the reconstructed rutile TiO2(011)-(2 × 1) surface upon 266 nm and 400 nm light excitation has been investigated quantitatively using the post-irradiation temperature-programmed desorption (TPD) method. Photochemical products such as formaldehyde, methyl formate and water, which result from the recombination of surface bridging hydroxyls through the abstraction of lattice oxygen atoms, have been identified under both 266 nm and 400 nm light irradiation. However, ethylene is detected only under 266 nm light irradiation.

Localized Excitation of Ti(3+) Ions in the Photoabsorption and Photocatalytic Activity of Reduced Rutile TiO2.

In reduced TiO2, electronic transitions originating from the Ti(3+)-induced states in the band gap are known to contribute to the photoabsorption, being in fact responsible for the material's blue color, but the excited states accessed by these transitions have not been characterized in detail. In this work we investigate the excited state electronic structure of the prototypical rutile TiO2(110) surface using two-photon photoemission spectroscopy (2PPE) and density functional theory (DFT) calculations. Using 2PPE, an excited resonant state derived from Ti(3+) species is identified at 2.