Palladium site ordering and the occurrence of superconductivity in Bi2Pd3Se2-xSx

The crystallographic and electronic structures of compounds related to parkerite (Bi2Ni3S2) are investigated with respect to the recently reported occurrence (Bi2Pd3Se2) and absence (Bi2Pd3S2) of superconductivity. Similarities and differences of the crystal structures are discussed within the series of solid solutions Bi2Pd3S2-xSex from powder and single crystal diffraction data. From crystal structure refinements, the question of different structures and settings of parkerite is discussed. Similar and different 2D and 3D partial Pd-Ch (Ch=S, Se) structures are related to half antiperovskite ordering schemes. To investigate the relation of low dimensional structures and the occurrence of superconductivity, electronic structures are analyzed by scalar-relativistic DFT calculations, including site projected DOS. ECOV and Fermi surfaces. (C) 2011 Elsevier Inc. All rights reserved.