Controlling surface reconstruction of SrTiO3(100) with adhesive outgassing

Abstract

We report on an unexpected effect of adhesives on the surface reconstruction of SrTiO3. We used two types of commercially available high-temperature adhesives, the platinum (Pt) and carbon (C) pastes, to mount two identical SrTiO3(100) substrates onto the sample holders, respectively. Two different surface reconstructions, namely 2 × 1 and (√13 × √13)-R33.7°, were obtained using Pt and C paste under nominally identical annealing conditions in ultrahigh vacuum (UHV). We show that the same two surface reconstructions can be obtained separately with annealing in UHV and in an O2 environment from identical substrates mounted without adhesives. Residual gas analysis of the adhesive outgassing suggests that the silicate binder in the C paste releases O2 at high temperatures while the Pt paste does not. Due to the limited amount of O2 that can be released from the C paste, a change of the surface reconstruction from (√13 × √13)-R33.7° to 2 × 1 was observed on the same substrate mounted with the C paste upon increasing the duration of annealing in UHV. Our study indicates that slight outgassing of certain adhesives may have a profound impact on the surface reconstruction of SrTiO3. This finding also provides an interesting new knob to tune the surface reconstruction of SrTiO3 in the same annealing environment.