Nanoscale structural variation observed on the vicinal SrTiO3(001) surface

Abstract

The vicinal (001) surface of a Nb-doped SrTiO3 single crystal has been investigated by scanning tunneling microscopy and low energy electron diffraction. The stepped surface prepared by annealing in ultrahigh vacuum at 250 °C exhibits a complex atomic structure composed of four types of reconstructions, which shows short-range variation within nanoscale regions. SrO layers show a c(6×2) structure being stable up to 1000 °C, while √13×√13-R33.7°, c(√13×√13)-R33.7°, and c(√2×√18)-R45° structures are formed on TiO2 layers, which disappear at 450–750 °C followed by the formation of 2×2 and √5×√5-R26.6° structures. These results indicate instability of the reconstructions on the TiO2 terminated surface due to the variation in Sr adatom density caused by multikinetic processes, in contrast to the thermodynamically stable SrO terminated surface.

Mechanical dissipation from charge and spin transitions in oxygen-deficient SrTiO3 surfaces

“…Bright features can be attributed to adatoms on top of the reconstructed ad-layer or oxygen hydroxyl (O−H) groups resulting from rest gases in the vacuum chamber, as it is known 44 that interstitial Ti atoms can cause a substantial increase in local surface reactivity and thus facilitate O−H group adsorption. Dark features could, on the other hand, indicate missing ad-islands in the reconstruction 11 , 45 or, considering that annealing was carried out at oxygen-poor conditions, more likely represent oxygen vacancies ( V O ) at or near the surface 42 , 46 . In agreement with that, the density of empty states 1 eV above Fermi level, which the STM probes, is high at all sites where a surface O atom is present.…”

Stripe charge ordering in SrO-terminated SrTiO3(001) surfaces

“…The c(6 × 2) unit cell is shown by a dotted line. diffraction (LEED) measurements [9,18]. In those measurements, the c(6 × 2) structure was assumed to be a surface reconstruction.…”

Atomic-scale investigations of perovskite oxide heteroepitaxy

“…4(b) and 4(c), respectively, demonstrate very sharp diffraction patterns, indicating an atomically flat STO surface, consistent with previous reports. 18) The flatness of this reconstructed surface was found to exceed that of the unreconstructed STO surface.…”