Anomalous charge transport of the parent antiferromagnet Bi2Sr2RCu2O8

The resistivity and the thermopower for Bi2Sr2Ca{1-x}RxCu2O8 single crystals are measured and analyzed with a special interest in the parent antiferromagnet insulators. Above room temperature, the parent insulators show an electric conduction confined in the CuO2 plane and a decreasing thermopower with temperature, which are very similar to those for high-$T_c$ cuprates. These data strongly suggest that essential anomalies of high-Tc cuprates inheres in the parent insulators.