Superconductivity in the overdoping state of the (Hg,Tl)(Ba,La)(2)CuO upsilon and (Hg,Tl)(2)Ba2CuO upsilon systems

The effect of Tl substitution for Hg in the Hg-Ba-Cu-O system has been investigated for a wide substitution range. The Tl substitution range of the single and double (Hg,Tl) layer systems was observed for 0-50% and 50-100%, respectively. Both the single and double (Hg,Tl) layer phases show the temperature dependence of resistivity of the metallic normal state and the overdoping state is confirmed by the substitution of Ba with La where the T-c increases with increasing La concentration. The T-c of the single (Hg,Tl) layer system, Hg1-xTlxBa2CuOv, decreases with increasing Tl concentration and becomes non-superconducting for x greater than or equal to 0.4. The double (Hg,Tl) layer system, Hg2-zTlzBa2CuOv, is non-superconducting due to the overdoping state.