Are There Ordering Effects in Ba(Pb,Bi)O3 and (Ba,K)BiO3?
A simple model is presented for the origin of the wide nonmetallic ranges in the (Ba, K)(Bi, Pb)O 3 alloy phase diagram, proposing that the semiconducting behaviour is caused by the presence of incommensurate oxygen breathing-type charge density waves as well as Bi/Pb ordering waves. The model is studied for large variety of supercell configurations using a simple, yet realistic tight-binding Hamiltonian. Good agreement with experiment is found. Crucial predictions of the model can be tested by diffuse elastic scattering experiments.
KeywordsAlloy Phase Diagram Charge Density Wave Semiconducting Behaviour Doping Range Bond Length Distribution
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