First-principles calculations of the surface relaxation and electronic structure of Zr(0001)

The multilayer relaxations of the Zr(0001) surface and the surface electronic structure are studied using first-principles total-energy and force calculations. The distance between the outermost two layers is 4.44.7 % smaller than the ideal interlayer spacing, while inner layers show oscillatory relaxations. We examined two possible termination sequences for the surface and found that the hcp surface termination is more stable by about 0.06 eV per surface atom as compared to the fcc terminated structure. We observed an increase in the local density of states (LDOS) for the surface atoms around the Fermi level relative to the bulk atoms. The increase in the LDOS is found to be closely related to the existence of surface states and resonances around the Fermi level.