Atomically flat single-terminated SrTiO3 (111) surface

Abstract

The authors have reproducibly obtained an atomically well-defined SrTiO3 (111) surface by a combined chemical etching and thermal annealing process. Although thermodynamic mixed termination is preferred as a means of suppressing the surface dipole, the kinetics-driven etching process, via selective etching of SrO34−, enables a single-terminated surface to be obtained. Subsequent O2 annealing of the etched surface produces a clear step-and-terrace structure. Atomically flat terraces and only one-unit-cell-high step edges are observed, signifying a single-terminated surface. This study might pave the way for constructing (111)-oriented perovskite oxide superlattices, which would be expected to demonstrate new and better physical phenomena and functionalities.

Layer-by-layer growth and growth-mode transition of SrRuO3 thin films on atomically flat single-terminated SrTiO3 (111) surfaces

“…Despite such a strong need for (111)-oriented oxide heterostructures, realizing the layer-by-layer growth of SRO films on SrTiO 3 (STO) (111) has yet to be reported because an atomically well-defined, single-2 terminated STO (111) surface has proved difficult to achieve. A recent accomplishment of successful fabrications of such a STO (111) surface by Chang et al,6 however, has opened the door to the layer-by-layer growth of SRO thin films, enabling SRO thin films to be integrated into (111)-oriented oxide heterostructures.…”

“…The specifics of the preparation of single-terminated STO (111) substrates were described in our previous paper. 6 For stoichometric ablation, a KrF excimer laser (wavelength λ=248 nm) was focused on a sintered SRO target with a fluence of 2.5 J/cm 2 .…”

“…Despite such a strong need for (111)-oriented oxide heterostructures, realizing the layer-by-layer growth of SRO films on SrTiO 3 (STO) (111) has yet to be reported because an atomically well-defined, single-2 terminated STO (111) surface has proved difficult to achieve. A recent accomplishment of successful fabrications of such a STO (111) surface by Chang et al,6 however, has opened the door to the layer-by-layer growth of SRO thin films, enabling SRO thin films to be integrated into (111)-oriented oxide heterostructures.In this letter, we report on anomalous growth-mode transitions at the initial growth of SRO thin films on single-terminated STO (111) substrates. We found that the growth modes during the initial growth stages are controllable by adjusting the growth rate (R g ) and growth temperature (T g ).…”

“…The specifics of the preparation of single-terminated STO (111) substrates were described in our previous paper. 6 For stoichometric ablation, a KrF excimer laser (wavelength λ=248 nm) was focused on a sintered SRO target with a fluence of 2.5 J/cm 2 .The oxygen pressure was maintained at 100 mTorr. During the SRO film deposition, the growth modes were monitored by in situ high-pressure reflection high-energy electron diffraction (RHEED) [Pascal].…”

Scanning tunneling microscopy of gate tunable topological insulator Bi2Se3thin films

“…The STO (111) substrates were cleaned by the method described in Ref. [22]. STO pieces, (3×4×0.1) mm 3 , were immersed in hot deionized water (70 °C) with ultrasonic agitation for 30 min.…”