Metallization of the resistivity tensor in ${\mathrm{Bi}}_2$${\mathrm{Sr}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_{\mathit{x}}$ through epitaxial intercalation

We have used iodine intercalation to alter the interplane interaction and the anisotropic resistivity tensor of the oxide superconductor ${\mathrm{Bi}}_2$ ${\mathrm{Sr}}_2$ ${\mathrm{CaCu}}_2$ ${\mathrm{O}}_{\mathit{x}}$. Real-space transmission electron microscopy images confirm that iodine is epitaxially intercalated between the Bi-O bilayers. In the normal state above ${\mathit{T}}_{\mathit{c}}$, the metallic ${\mathrm{CuO}}_2$ plane sheet resistance is unaffected by intercalation, while the out-of-plane conduction is dramatically changed from semiconductorlike to metalliclike. This result is inconsistent with some of the theoretical predictions based on holon-spinon scattering.