INPLANE ANISOTROPIC TRANSPORT-PROPERTIES OBSERVED IN EPITAXIAL BI2(SR,CA)3CU2OX FILMS GROWN ON TILTED (001)SRTIO3 SUBSTRATE

We report on large in-plane anisotropic transport properties observed in epitaxial Bi2(Sr,Ca)3Cu2Ox films grown on tilted (001)SrTiO3 substrate. By tilting the surface normal axis about 4-degrees toward [111]SrTiO3, regular steps and terraces were formed on the substrate surface and perfect alignment of film b axis with incommensurate modulation along [110]SrTiO3 was realized. The film c axis was perpendicular to the (001)SrTiO3 terrace, thus the film c axis grew tilted 4-degrees toward [111] from surface normal due to the surface inclination. In those epitaxial configurations, the in-plane resistivity along the step direction (rho-[110]) involved the contribution from the c-axis (rho-(c)) component, and we observed the large resistivity anisotropy between a- and b- direction of the film. The transport along a axis(pa) showed a low resistivity with metallic temperature dependence while the resistivity along the step direction(rho-[110]) was higher and semiconductive. The ratio of rho-c/rho-a almost-equal-to 10(4) estimated in this experiment agrees well with the anisotropy observed in the bulk single crystal.