Scanning tunneling microscopy observation of Fe deposited SrTiO₃(100)-(√13 × √13)-R33.7° surface

Abstract

Scanning tunneling microscopy imaging of Fe deposited SrTiO₃(100)-(√13 × √13)-R33.7° surface is presented. Low-energy electron diffraction patterns showed that the surface reconstruction remained after Fe deposition at room temperature. Fe deposition generated defects, including oxygen vacancies, on the SrTiO₃(100)-(√13 × √13)-R33.7° surface. These defects have a periodicity with the c(√13 × √13) symmetry. Scanning tunneling spectroscopy demonstrated the formation of two types of defects: one had the same density of state with defects on the bare SrTiO₃(100)-(√13 × √13)-R33.7° surface, and the other had a narrow band gap structure. These results are attributed the formation of a two-dimensional hole gas at the FeO_x/SrTiO₃(100) interface.