Corentin Morice, Emilio Artacho, Sian E. Dutton, Daniel Molnar, Hyeong-Jin Kim, Siddharth S. Saxena
Newly discovered Bi-S-O compounds remain an enigma in attempts to establish a coherent understanding of their electronic, structural and underlying emergent superconducting properties. Recent extensive chemical study of Bi$_{4}$O$_{4}$S$_{3}$ has shown this compound to be actually a mixture of two phases, Bi$_{2}$OS$_{2}$ and Bi$_{3}$O$_{2}$S$_{3}$, and only the latter being the superconducting one. Here we explore, using density functional theory calculations, the electronic structure of both the phases, as well as the effect of the introduction of stacking faults in the latter compound. Our results demonstrate that the S$_{2}$ layers in Bi$_{3}$O$_{2}$S$_{3}$ are responsible for the electron doping of the BiS$_{2}$ bands, and that the electrons are actually accumulated in the BiS planes. We also show that the introduction of defects in the stacking diminishes the effects of doping which would suppress superconductivity.
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http://arxiv.org/abs/1305.1201
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