EPITAXIAL FILM GROWTH OF THE CHARGE-DENSITY-WAVE CONDUCTOR RB0.30MOO3ON SRTIO3(001)

Thin films of the charge-density-wave compound Rb0.30MoO3 (blue bronze ) have been grown on SrTiO3 (001) substrates. The films have been anal yzed with atomic force microscopy and x-ray diffraction. The growth in itially proceeds in the three-dimensional island growth mode (Volmer-W eber mode) with dropletlike islands that are highly uniform and fully relaxed. Epitaxial growth is observed: the fourfold symmetry of the Sr TiO3(001) surface results in four crystallographic orientations. Thick films show cluster formations that differ in size and form from the i slands that appear at the initial stage of growth. They are larger and have an asymmetric shape with clear facets. X-ray diffraction on thic k films shows a decrease of both the in-plane and out-of-plane texture . The data are explained with a simple model that involves blue bronze layer growth over the facets of the clusters. The model indicates tha t the crystalline correlation length perpendicular to the charge-densi ty-wave axis is smaller than the dimensions of the grains. The implica tions of the model on the electrical transport are discussed.