Structure, dynamics and thermodynamics of a metal chiral surface: Cu(532)

The structure, vibrational dynamics and thermodynamics of a chiral surface, Cu(532), have been calculated using a local approach and the harmonic approximation, with interatomic potentials based on the embedded atom method. Relaxation of the atomic positions to the optimum configuration results in a complex relaxation pattern with strong contractions in the bond length of atoms near the kink and the step sites and an equivalently large expansion near the least under-coordinated surface atoms. The low coordination of the atoms on the surface substantially affects the vibrational dynamics and thermodynamics of this system. The local vibrational density of states shows a deviation from the bulk behaviour that persists down to the tenth layer, resulting in a substantial contribution of the vibrational entropy to the excess free energy amounting to about 90 meV per unit cell at 300 K.