Synthesis, Crystal Structure, and Physical Properties of New Layered Oxychalcogenide La2O2Bi3AgS6

摘要

We have synthesized a new layered oxychalcogenide La2O2Bi3AgS6. Fromsynchrotron X-ray diffraction and Rietveld refinement, the crystal structure ofLa2O2Bi3AgS6 was refined using a model of the P4/nmm space group with a =4.0644(1) {\AA} and c = 19.412(1) {\AA}, which is similar to the relatedcompound LaOBiPbS3, while the interlayer bonds (M2-S1 bonds) are apparentlyshorter in La2O2Bi3AgS6. The tunneling electron microscopy (TEM) imageconfirmed the lattice constant derived from Rietveld refinement (c ~ 20 {\AA}).The electrical resistivity and Seebeck coefficient suggested that theelectronic states of La2O2Bi3AgS6 are more metallic than those of LaOBiS2 andLaOBiPbS3. The insertion of a rock-salt-type chalcogenide into the van derWaals gap of BiS2-based layered compounds, such as LaOBiS2, will be a usefulstrategy for designing new layered functional materials in the layeredchalcogenide family.