Simulation of the oxygen-atom vacancy in the high temperature superconductor TlBa<sub>2</sub>Ca<sub>n-1</sub>Cu<sub>n</sub>O<sub>2n+2.5</sub> (n=1)
Y Q Jia; Y Q Jia; Inst. of Appl. Chem., Acad. Sinica, Changchun, China
Журнал:
Journal of Physics: Condensed Matter
Дата:
1991-04-22
Аннотация:
Simulation calculations for the oxygen-atom vacancy in the high temperature superconductor TlBa<sub>2</sub>Ca<sub>n-1</sub>Cu<sub>n</sub>O<sub>2n+2.5</sub> (n=1) have been performed by means of the tight-binding approximation based on the EHMO method. The results indicate that the effect of the oxygen-atom vacancy on the charge distributions at the Tl-, Ba-, Cu- and O-atom sites is appreciably different and that there may exist two kinds of Cu cation with different net charges ( approximately +3.0 or approximately +1.0) due to the oxygen-atom vacancy in the lattice. The electric field gradient at the site of the oxygen-atom vacancy has been calculated. The position of the oxygen-atom vacancy which favours the high temperature superconductivity of TlBa<sub>2</sub>Ca<sub>n-1</sub>Cu<sub>n</sub>O<sub>2n+2.5</sub> (n=1) has been discussed.
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