Oxygen vacancies on SrO-terminated<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>SrTi</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mn>001</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math>surfaces studied by scanning tunneling spectroscopy

Sitaputra, Wattaka; Sivadas, Nikhil; Skowroński, Marek; Xiao, Di; Feenstra, R. M.

doi:10.1103/physrevb.91.205408

Cited by 22 publications

(37 citation statements)

References 77 publications

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“…[27] Since NC-AFM images ultimately mirror the surface potential, such charge modulations appear as enhanced roughness. [27,28,30,41,64] Putting all of the pieces together, we therefore assign the initial decline in surface roughness at modest temperatures to improved surface ordering and eliminating surface contamination, while the subsequent increase for higher temperatures is likely a manifestation of the heightened charge disorder described above. is found to rise again for values above ≈1100 K.…”

Section: Evolution Of Surface Roughness On Terraces As a Function Of mentioning

confidence: 99%

“…More specifically, the electric field due to the negative potential causes a downward band bending, which attracts the electrons towards the surface. [27,28,64] Conversely, when a positive bias is applied, electrons are pushed into the bulk through an 'upwards band bending, [28,64] while a negative image charge is induced at the tip apex ('inversion'); note that both regimes lead to an additional attractive force between tip and sample that causes the feedback to enlarge the distance between tip and sample, which results in larger z-piezo values.…”

Section: Evolution Of Surface Roughness On Terraces As a Function Of mentioning

confidence: 99%

“…Since both layers are thermodynamically stable and non-polar, a (100) surface in principle can expose either of the two terminations, making the properties of the surface a local characteristic. [14][15][16][17][18][19][20][21][22][23] Given that SrO-and TiO 2 -terminated terraces differ substantially in their chemical and electrical properties, [14,[24][25][26][27][28][29] the characteristics of films grown on nominally mixedterminated substrates will vary locally as well. Similar to many other perovskite metal oxides, SrTiO 3 commonly reconstructs; the plethora of reconstructions identified include (2×1), (2×2), (4×4), c(4×2), c(4×4), c(6×2), (√5×√5)-R26.6°, and (√13×√13)-R33.7° structures.…”

Section: Introductionmentioning

confidence: 99%

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Surface phase, morphology, and charge distribution transitions on vacuum and ambient annealedSrTiO3(100)

et al. 2016

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The surface structures of SrTiO 3 (100) single crystals were examined as a function of annealing time and temperature in either oxygen atmosphere or ultra-high vacuum (UHV) using noncontact atomic force microscopy (NC-AFM), Auger electron spectroscopy (AES), and low-energy electron diffraction (LEED). Samples were subsequently analyzed for the effect the modulation of their charge distribution had on their surface potential. It was found that the evolution of the SrTiO 3 surface roughness, stoichiometry, and reconstruction depends on the preparation scheme. Surface roughness evolved non-monotonically with UHV annealing temperature, which is explained by electrostatic modulations of the surface potential caused by increasing oxygen depletion. This was further corroborated by experiments in which the apparent roughness tracked in NC-AFM could be correlated with changes in the surface charge distribution that were controlled by applying a bias voltage to the sample. Based on these findings, it is suggested that careful selection of preparation procedures combined with application of an electric field may be used to tune the properties of thin films grown on SrTiO 3 .

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Section: Evolution Of Surface Roughness On Terraces As a Function Of mentioning

confidence: 99%

Section: Evolution Of Surface Roughness On Terraces As a Function Of mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surface phase, morphology, and charge distribution transitions on vacuum and ambient annealedSrTiO3(100)

et al. 2016

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“…Our DFT calculations simulated cation intermixing as the probable cause for the interface asymmetry, which matches closely to our experimental results. While intermixing at the interface successfully explains the difference in band alignments for the two devices, a different amount of oxygen vacancies at the S-Nb:STO and T-Nb:STO interfaces could also play an important role in the interfacial structural distortion [42]. The presence of oxygen vacancy in the SrO plane significantly reduces the electron repulsion in that direction (c axis) and that results in an increased displacement between the atomic planes at the interface.…”

Section: Discussionmentioning

confidence: 98%

Engineering interfacial energy profile by changing the substrate terminating plane in perovskite heterointerfaces

et al. 2016

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Atomically engineered oxide heterointerfaces show a range of novel phenomena not present in their bulk form, thus providing an additional knob to tune the functional properties across such interfaces. Here we show that for an oxide Schottky interface between metallic SrRuO 3 and semiconducting Nb doped SrTiO 3 (Nb:STO) the terminating surface of the substrate plays a crucial role in determining the electronic transport across it. Interestingly this is achieved by engineering a monolayer of a charge-neutral SrO layer across the Schottky interface and not by the insertion of charged layers at the interface, as has been demonstrated earlier. These changes in the energy-band line-up across a symmetric interface indicate the presence of different polar characters at the SrO and TiO 2 terminations of the substrate. Owing to the presence of the same AO layer (SrO) in both SrRuO 3 and Nb:STO, we propose an intermixing of Ru and Ti ions across the interface for the SrO terminated Nb:STO substrate. First-principles density functional theory calculations on these systems conform with our experimental findings, and indicate a resultant shift in the interfacial atomic plane stacking of SrRuO 3 at the intermixed interface, leading to a modification of the electrostatic potential at the interface. The interdependence between the interfacial band alignment to the local atomic plane displacement across an intrinsically nonpolar oxide heterointerface is a key mechanism in realizing novel electronic properties in oxide based devices.

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“…On similar grounds, the vacancy-induced doping enhances correlations in the LAO/STO interface. Puzzling interplay between itinerant and localized electrons in STO-based surfaces and interfaces is indeed suggested from scanning-tunneling spectroscopy [20][21][22], magnetoresistance and anomalous Hall-effect measurements [23], resonant x-ray scattering [24,25] and photoemission [6,7,26].…”

Section: Introductionmentioning

confidence: 91%

Interface exchange processes inLaAlO3/SrTiO3induced by oxygen vacancies

Behrmann

Lechermann

2015

Phys. Rev. B

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Understanding the role of defects in oxide heterostructures is crucial for future materials control and functionalization. We hence study the impact of oxygen vacancies (OVs) at variable concentrations on orbital-and spin exchange in the LaAlO3/SrTiO3 interface by first principles many-body theory and real-space model-Hamiltonian techniques. Intricate interplay between Hubbard U and Hund's coupling JH for OV-induced correlated states is demonstrated. Orbital polarization towards an effective eg state with predominant local antiferromagnetic alignment on Ti sites near OVs is contrasted with t2g(xy) states with ferromagnetic tendencies in the defect-free regions. Different magnetic phases are identified, giving rise to distinct net-moment behavior at low and high OV concentrations. This provides a theoretical basis for prospective tailored magnetism by defect manipulation in oxide interfaces.

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Oxygen vacancies on SrO-terminatedSrTiO3(001)surfaces studied by scanning tunneling spectroscopy

Cited by 22 publications

References 77 publications

Surface phase, morphology, and charge distribution transitions on vacuum and ambient annealedSrTiO3(100)

Surface phase, morphology, and charge distribution transitions on vacuum and ambient annealedSrTiO3(100)

Engineering interfacial energy profile by changing the substrate terminating plane in perovskite heterointerfaces

Interface exchange processes inLaAlO3/SrTiO3induced by oxygen vacancies

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