Ripple structure on Ag(110) surface induced by ion sputtering

The morphology of the Ag(110) surface after Ar+ ion sputtering has been studied by a variable temperature scanning tunneling microscope. For ion energies greater than 800 eV and in the temperature range 270 < T-s < 320 K (where T-S is the sputtering temperature), a peculiar ripple structure well aligned along the [1(1) over bar0$] direction and independent of the ion beam angle has been observed. A simple model of this effect, based on the anisotropy and on the temperature hierarchy of the Ag adatom and vacancy surface diffusion, explains the observed features.