Study of the electronic and atomic structure of thermally treated SrTiO₃(110) surfaces

Abstract

The electronic structure of heated SrTiO 3 (110) surfaces was investigated with metastable impact electron spectroscopy and ultraviolet photoelectron spectroscopy (He(I)). Scanning tunnelling microscopy and atomic force microscopy (AFM) were used to study the topology of the surface. The crystals were heated up to 1000• C under reducing conditions in ultrahigh vacuum or under oxidizing conditions in synthetic air for 1 h, respectively. Under both conditions microfacetting of the surface is observed. The experimental results are compared with ab initio Hartree-Fock calculations, also presented here, carried out for both ideal and reconstructed SrTiO 3 (110) surfaces. The results give direct evidence for Ti termination of the faceted TiO 2 rows.

Microscopic characterization of Fe nanoparticles formed on SrTiO3(001) and SrTiO3(110) surfaces

“…STO(110) surfaces are terminated with TiO planes with the possibility of oxygen depletion [25]. This type of surface structure is also reported with samples annealed in UHV at comparatively low temperatures [34–36] and matches with our results. However, crystal deformation presumably due to ion-beam thinning is also observed in our case [25].…”

The interaction of H2O with Fe‐doped SrTiO3(100) surfaces

“…This surface is slightly contaminated from residual gas components which are desorbed at a temperature of 560 K. After this smooth cleaning procedure, contribution from surface defects in the band gap appear around 0.9 eV below the Fermi level. These states in the band gap are well known oxygen defects which result in the occupation of surface Ti 3d orbitals 21–23, 31, 32…”

“…Figure 7 shows MIES spectra of the band gap between the Fermi level and E B = 5 eV. The Fermi level is pinned to the conduction band, the gap width of about 3 eV corresponds to previous findings 21–25. The top spectrum shows the surface directly after sputtering.…”

“…7 show, that defect states may be observed obviously in the band gap of sputtered SrTiO 3 (100) only with MIES. They correspond to Ti 3d states located just below the Fermi level, which has been observed for donor‐doped SrTiO 3 surfaces with MIES previously 21–23. Such defects are not observed before sputtering.…”

Reaction Mechanism and Structure-Reactivity Relationships in the Stereospecific 1,4-Polymerization of Butadiene Catalyzed by Neutral Dimeric Allylnickel(II) Halides [Ni(C3H5)X]2 (X−=Cl−, Br−, I−): A Comprehensive Density Functional Theory Study

“…These processes take place in the vicinity of the SrTiO 3 surface and strongly depend on the SDOS. Therefore, surface analytical techniques, especially MIES, are suited best for the investigation of this important process 19–25…”