We discuss the electronic structure, lattice dynamics and electron-phonon interaction of newly discovered superconductor LaO0.5F0.5BiS2 using density functional based calculations. A strong Fermi surface nesting at k=(π,π,0) suggests a proximity to charge density wave instability and leads to imaginary harmonic phonons at this k point associated with in-plane displacements of S atoms. Total energy analysis resolves only a shallow double-well potential well preventing the appearance of static long-range order. Both harmonic and anharmonic contributions to electronphonon coupling are evaluated and give a total coupling constant λ ≃ 0.85 prompting this material to be a conventional superconductor contrary to structurally similar FeAs materials. Here, the basic structural unit is the BiS 2 layer which is similar to the Cu-O planes in Cu-based superconductors[1] and the Fe-A (A=P, As, Se, Te) planes in iron pnictides [5]. A chance to explore superconductivity and increase T c in these new compounds has already resulted in a lot of work that appeared shortly after the discovery [1,7,[9][10][11][12][13][14][15][16]. Hall effect measurements reveal multiband features and suggest the superconducting pairing occurs in one-dimensional chains [10]. It was proposed that these compounds are type II superconductors and good candidates for thermoelectric materials [11]. Electrical resistivity measurements under pressure reveal that Bi 4 O 4 S 3 and La(O,F)BiS 2 have different T c versus pressure behavior, and the Fermi surface of La(O,F)BiS 2 may be located in the vicinity of some instabilities [12]. A two p bands electronic model has been proposed based on band structure calculation [13], and a

A highly ordered titanium dioxide nanotube arrays (HOTDNA) electrode was prepared in hydrofluoric acid solution by electrochemical anodization technique on a pure titanium sheet. The HOTDNA electrode was characterized by FE-SEM microscopy, X-ray diffraction, and UV-vis spectra. The linear-sweep photovoltammetry response on the HOTDNA electrode is presented in this work. The photogenerated current of 0.3 mA/cm2 was observed significantly upon illumination with applied potential of 0.5 V in the UV regions at the central wavelength of 253.7 nm. Photoelectrocatalytic (PEC) and photocatalytic (PC) activities of the HOTDNA electrode were evaluated in the degradation of methyl orange (MeO) in aqueous solution. A set of optimized conditions such as anodic potential, calcinations temperature, and MeO concentration on the PEC activity was investigated. The PEC and PC activities of HOTDNA electrode were compared. We concluded that the HOTDNA electrode was an effective photoelectrode for achieving an enhanced MeO degradation.

We have performed an angle-resolved photoemission spectroscopy study of the BiS 2 -based superconductor Nd(O,F)BiS 2 . Two small electron-like Fermi surfaces around X (π, 0) are observed, which enclose 2.4% and 1.1% of the Brillouin zone area, respectively, corresponding to an electron doping of 7% per Bi site. The lowenergy spectrum consists of a weakly-dispersing broad hump and a dispersive branch, which follows well the calculated band dispersion. This hump is drastically suppressed with increasing temperature, while the dispersive branch is essentially unaffected. The anomalous thermal effect indicates a highly interacting electronic state, in which the superconducting pairing develops.

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