Metastable phase of vanadium

The epitaxial Bain path for vanadium, calculated by first-principles theory, reveals the existence of a metastable body-centered-tetragonal (bct) phase with $c/a=1.78.$ Experiments aimed at stabilizing this phase by pseudomorphic epitaxy on a Ni{001} substrate were successful insofar as the ultrathin films grown have a bct structure with $c/a$ between 1.73 and 1.77. The bulk structure of the V films was determined by quantitative low-energy electron diffraction, but the accuracy of the results is worse than usual owing to high densities of defects in the grown films.