Step-step interaction energy on Cu(111) vicinal surfaces

We have measured the terrace width distribution on copper (111) vicinal sur faces with (100) steps. For all surfaces, the distribution is well fitted b y a Gaussian. The width of the Gaussian scales with the mean terrace width L, which is indicative of a repulsive 1/L-2 interaction potential between s teps. We determine an interaction strength of the potential of 3.2 +/- 0.2 meV per atom length. From the temperature-dependent analysis of the step-st ep distance distribution, we find a kink formation energy for (100) steps o f 0.12 +/- 0.03 eV, which is consistent with previous measurements of the k ink energy on copper (100) vicinal surfaces.