Surface atomic structure and energetics of tantalum

Electronic and structural properties of the unreconstructed low-index Ta surfaces are studied from first principles. Results for multilayer relaxations, surface energy, and work function of fully relaxed slabs are presented. All considered surfaces exhibit a large contraction of the first interplanar distance, which at the most open (1 1 1) surface amounts to 26%. The calculated surface energy anisotropy is discussed in connection with the stability of surfaces, the equilibrium shape of tantalum crystal, and the adsorbate induced faceting.