METASTABLE FILM GROWTH OF CR ON CU(001)

The growth and structure of Cr films (0-30 nominal monolayers (ML)) on Cu(001) held at room temperature have been investigated by photoemiss ion, photoelectron diffraction and low energy electron diffraction tec hniques. The films exhibit ordered body-centred cubic (bcc) domains ty pically similar to 10 lattice parameters in size with Cr(110)parallel to(Cu(001) and Cr[1<($$)over bar>11]parallel to Cu[110] and equivalent epitaxial orientations. LEED and photoelectron diffraction reveal a s ubstantial deviation from relaxed bce structure in ultra-thin films (< 3 ML) with an in-plane distortion and expansion and an interlayer cont raction of the Cr(110) layers. The initial mode of growth is character ized by the formation of multilayer islands and 90% substrate coverage occurs by similar to 4 ML.