Competition of terrace and step-edge sputtering under oblique-incidence ion impact on a stepped Pt(1 1 1) surface

Using molecular-dynamics simulation, we study the sputtering of a Pt(1 1 1) surface under oblique and glancing incidence 5 keV Ar ions. For incidence angles larger than a critical angle ϑcϑc, the projectile is reflected off the surface and the sputter yield is zero. We discuss the azimuth dependence of the critical angle ϑcϑc with the help of the surface corrugation felt by the impinging ion. If a step exists on the surface, sputtering occurs also for glancing incidence ϑ>ϑcϑ>ϑc. We demonstrate that for realistic step densities, the total sputtering of a stepped surface may be sizable even at glancing incidence.