Superconductivity induced by current injection into non-superconducting Bi2Sr2CaCu2O8

We already have shown that we can change the carrier concentration of Bi2Sr2CaCu2O8+δ single crystals by current injection along the c-axis. In this work, we focus on the interesting question: Can we induce superconductivity in non-superconducting Bi2Sr2CaCu2O8 merely by current injection? We report on current-injection experiments of fully oxygen depleted Bi2Sr2CaCu2O8 in which superconductivity was not observed down to 4.2 K. In order to eliminate the contact resistance of the highly resistive depleted material, we have fabricated double cross-bar crystal stacks. We have increased the c-axis conductivity by carrier injection until superconductivity above 4.2 K was observed. Doping the sample further by current injection, optimum-doped and even overdoped states were obtained. The current injection effect was persistent up to annealing temperatures of approximately 270 K.