We report superconductivity in an iron-based layered oxy-pnictide LaOFeP. LaOFeP is composed of an alternate stack of lanthanum oxide (La3+O2-) and iron pnictide (Fe2+P3-) layers. Magnetic and electrical resistivity measurements verify the occurrence of the superconducting transition at approximately 4 K.

A low noise single-transistor transimpedance preamplifier for Fourier-transform mass spectrometry using a T feedback network Rev. Sci. Instrum. 83, 094102 (2012) Charge carrier dynamics and interactions in electric force microscopy J. Chem. Phys. 137, 124701 (2012) Effects of microwave annealing on electrical enhancement of amorphous oxide semiconductor thin film transistor Appl. Phys. Lett. 101, 132901 (2012) Impact of oxygen annealing on high-k gate stack defects characterized by random telegraph noise Appl. Phys. Lett. 101, 122105 (2012) Graphene based field effect transistor for the detection of ammonia

Crystal structures, optoelectronic properties, and electronic structures of layered oxychalcogenides BiCuOCh (Ch ) S, Se, Te) have been compared to those of LaCuOCh, with an emphasis on the electronic configurations of Bi 3+ (5d 10 6s 2 ) and La 3+ (5d 0 6s 0 ). The BiCuOCh series were expected to exhibit better hole-transport properties than the LaCuOCh series because the pseudo-closed-shell 6s 2 electronic configuration of the Bi 3+ cation was expected to form valence band maxima (VBM) by admixing with the p orbitals of the Ch anions. However, the two series of compounds exhibited similar electrical properties, suggesting that the contribution of the Bi 6s orbitals to the VBM is small in BiCuOCh. The crystal structures and optical properties showed distinct differences; for example, the band gaps of BiCuOCh were smaller than those of LaCuOCh. These findings can be understood on the basis of the electronic structures obtained by photoelectron spectroscopy and density functional theory calculations. The Bi 6s orbitals form stronger and deeper chemical bonds with the O 2p orbitals than with Ch p orbitals and are located ∼2 eV below the VBM, which is mainly formed from the Cu 3d and Ch p orbitals. Thus, the Bi 6s 2 configuration contributes little to the VBM, and BiCuOCh and LaCuOCh have similar hole-transport properties. Also, the smaller band gaps of BiCuOCh result from the deepening of the conduction-band-minima levels, which are composed of unoccupied Bi 6p orbitals.