Oscillations in oblique-incidence optical reflection from a growth surface during layer-by-layer epitaxy

Abstract

We report the observation of hundreds of oscillations in oblique-incidence optical reflectivity difference from a growth surface of Nb-doped ${\text{SrTiO}}_{3}(100)$ during a continuous, pulsed-laser deposition. Similar to in-phase specular reflection of thermal helium atoms or electrons, the optical oscillations originate from an oscillatory change in step density on the surface and the different optical dielectric response of step edge atoms (or unit cells) from those in the flat terraces.