Metastable body-centered-tetragonal phase of vanadium on Cu{001}

Pseudomorphic ultrathin films of vanadium on Cu{001} up to about 14 Angstro m thick have a body-centered-tetragonal structure with a = 2.556 Angstrom a nd c = 4.40 +/- 0.10 Angstrom, as determined by quantitative low-energy ele ctron-diffraction analysis. Despite the low accuracy of the quantitative re sults, which is due to the high densities of defects and disorder in the gr own films, use of the epitaxial Bain path leads to unambiguous identificati on of the films' structure as a strained state of the metastable equilibriu m bet phase of vanadium at c/a = 1.78, rather than a strained state of the bcc ground state at c/a = 1. [S0163-1829(99)03620-6].