Virginia TechStasevich, T. J.Einstein, T. L.Zia, Royce K. P.Giesen, M.Ibach, H.Szalma, F.2014-05-072014-05-072004-12Stasevich, T. J.; Einstein, T. L.; Zia, R. K. P.; Giesen, M.; Ibach, H.; Szalma, F., "Effects of next-nearest-neighbor interactions on the orientation dependence of step stiffness: Reconciling theory with experiment for Cu(001)," Phys. Rev. B 70, 245404 DOI: http://dx.doi.org/10.1103/PhysRevB.70.2454041098-0121http://hdl.handle.net/10919/47836Within the solid-on-solid (SOS) approximation, we carry out a calculation of the orientational dependence of the step stiffness on a square lattice with nearest- and next-nearest-neighbor interactions. At low temperature our result reduces to a simple, transparent expression. The effect of the strongest trio (three-site, nonpairwise) interaction can easily be incorporated by modifying the interpretation of the two pairwise energies. The work is motivated by a calculation based on nearest neighbors that underestimates the stiffness by a factor of 4 in directions away from close-packed directions, and a subsequent estimate of the stiffness in the two high-symmetry directions alone that suggested that inclusion of next-nearest-neighbor attractions could fully explain the discrepancy. As in these earlier papers, the discussion focuses on Cu(001).en-USIn Copyrightinitio molecular-dynamicstotal-energy calculationskink-formationenergiesembedded-atom-methodwave basis-setmetal-surfacesequilibrium shapesconsequencestransitionTemperaturephysics, condensed matterArticle - Refereedhttp://journals.aps.org/prb/abstract/10.1103/PhysRevB.70.245404https://doi.org/10.1103/PhysRevB.70.245404