Hl. Kao et al., SYSTEMATICS OF TRANSPORT ANISOTROPY IN SINGLE-DOMAIN LA2-XSRXCUO4 FILMS, Physical review. B, Condensed matter, 48(13), 1993, pp. 9925-9928
The ability to control the tilt angle of CuO2 planes with respect to t
he film surface has led to successful synthesis of single-domain, epit
axial La2-xSrxCuO4 filMS of (103) and (109) orientations corresponding
to tilt angles of 21-degrees and 49-degrees, respectively. The system
atics of the c-axis resistivity and transport anisotropy rho(c)/rho(ab
) have been studied as a function of Sr doping varying from 0.04 to 0.
34 over 2 less-than-or-equal-to T less-than-or-equal-to 800 K. The tem
perature dependence of the c-axis resistivity evolves from semiconduct
inglike behavior in the lightly doped and optimally (superconducting)
doped regions (x less-than-or-equal-to 0.15) to metallic behavior in t
he heavily doped region (x greater-than-or-equal-to 0.25), displaying
a notable discontinuity of the slope at the tetragonal-orthorhombic ph
ase transformation. The crossover from two-dimensional metallic transp
ort to strongly anisotropic three-dimensional metallic transport was o
bserved near the superconducting phase boundary (x is similar to 0.22)
. The evolution of transport anisotropy rho(c)/rho(ab) closely resembl
es the evolution of the electronic orbital character of doping-induced
holes, hence suggesting a connection between the two-dimensional elec
tronic structure and superconductivity.