Pushing the detection of cation nonstoichiometry to the limit

Riva, Michele; Franceschi, Giada; Lu, Qiyang; Schmid, Michael; Yildiz, Bilge; Diebold, Ulrike

doi:10.1103/physrevmaterials.3.043802

Cited by 19 publications

(36 citation statements)

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“…Importantly, the surface structure evolves along the phase diagram for submonolayer changes in the Sr and Ti composition in the near-surface region (bottom of Fig. 1) [20]. This has strong implications for the growth of SrTiO 3 (110) films: Under nonstoichiometric conditions, the excess components float to the surface, changing its composition.…”

Section: Introductionmentioning

confidence: 99%

“…All three low-index surfaces of SrTiO 3 adjust their surface structure in response to a change in surface stoichiometry [20][21][22][23][24][25][26][27][28][29]. We opt for the (110) orientation because of the reproducibility and detailed knowledge of its surface reconstructions, some of which are reported for reference in the phase diagram of Fig.…”

Section: Introductionmentioning

confidence: 99%

“…We opt for the (110) orientation because of the reproducibility and detailed knowledge of its surface reconstructions, some of which are reported for reference in the phase diagram of Fig. 1 [20,30]. These reconstructions are TiO x terminated, and form to compensate for the intrinsic polar instability of the bulk-truncated (110) surface [31].…”

Section: Introductionmentioning

confidence: 99%

“…This has strong implications for the growth of SrTiO 3 (110) films: Under nonstoichiometric conditions, the excess components float to the surface, changing its composition. Thus, the surface of a film changes its structure during nonstoichiometric growth and evolves along the surface phase diagram [20].…”

Section: Introductionmentioning

confidence: 99%

“…These phases are equilibrium structures governed by the near-surface stoichiometry: Submonolayer deposition (arrows at the bottom) of Sr or Ti, followed by high-temperature annealing in O 2 ambient, allows to move continuously and reversibly between the surface structures. Here one monolayer (ML) corresponds to the number of Sr (or Ti) sites in a (SrTiO) 4+ plane of SrTiO 3 (110), i.e., 1 ML = 4.64×10 14 function of the fluence of the ultraviolet (UV) laser [20]. We find that low laser fluences result in Sr-enriched films, consistently with literature reports [14,15,33]; instead, above a certain threshold, films grow close to stoichiometric or slightly Ti rich, in agreement with some previous results [33], but not as strongly Ti rich as observed elsewhere [14,15].…”

Section: Introductionmentioning

confidence: 99%

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Epitaxial growth of complex oxide films: Role of surface reconstructions

Riva

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Schmid

et al. 2019

Phys. Rev. Research

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Achieving atomically flat and stoichiometric films of complex multicomponent oxides is crucial to integrating these materials in both established and emerging technologies. While pulsed laser deposition (PLD) can in principle produce these high-quality films, growth experiments often result in unsatisfactory morphologies with rough surfaces and nonstoichiometric compositions. To understand the cause, the growth needs to be followed at an atomic level from its early stages as a function of the growth conditions. By combining PLD with atomically resolved scanning tunneling microscopy, as well as surface spectroscopic and diffraction techniques, we address the origin of surface roughening in SrTiO 3 (110) homoepitaxial films and pinpoint optimal growth conditions. We highlight the importance of surface reconstructions at all stages of growth: The different sticking on coexisting surface structures is responsible for the roughening of SrTiO 3 (110) films and affects their stoichiometry.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Epitaxial growth of complex oxide films: Role of surface reconstructions

Riva

Franceschi

Schmid

et al. 2019

Phys. Rev. Research

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Identifying Ionic and Electronic Charge Transfer at Oxide Heterointerfaces

et al. 2020

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The ability to tailor oxide heterointerfaces has led to novel properties in low‐dimensional oxide systems. A fundamental understanding of these properties is based on the concept of electronic charge transfer. However, the electronic properties of oxide heterointerfaces crucially depend on their ionic constitution and defect structure: ionic charges contribute to charge transfer and screening at oxide interfaces, triggering a thermodynamic balance of ionic and electronic structures. Quantitative understanding of the electronic and ionic roles regarding charge‐transfer phenomena poses a central challenge. Here, the electronic and ionic structure is simultaneously investigated at the prototypical charge‐transfer heterointerface, LaAlO3/SrTiO3. Applying in situ photoemission spectroscopy under oxygen ambient, ionic and electronic charge transfer is deconvoluted in response to the oxygen atmosphere at elevated temperatures. In this way, both the rich and variable chemistry of complex oxides and the associated electronic properties are equally embraced. The interfacial electron gas is depleted through an ionic rearrangement in the strontium cation sublattice when oxygen is applied, resulting in an inverse and reversible balance between cation vacancies and electrons, while the mobility of ionic species is found to be considerably enhanced as compared to the bulk. Triggered by these ionic phenomena, the electronic transport and magnetic signature of the heterointerface are significantly altered.

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Elucidating the Surface Properties of Sr₃PbO Inverse‐Perovskite Topological Insulator: A First‐Principles Study

Bilal,

Alay-e-Abbas,

Abbas

et al. 2023

Physica Status Solidi (b)

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The emergence of robust surface electronic states in topological insulators such as bulk Sr3PbO inverse‐perovskite makes them suitable candidates for spintronic devices and solid‐state quantum computers. Herein, the atomic structure, surface energetics, and electronic properties of Sr3PbO inverse‐perovskite Sr2O (SO)‐terminated and SrPb‐terminated (001) surfaces are examined using density functional theory. A comparison of the computed structural properties of SO‐termianted and SrPb‐terminated (001) surfaces reveals maximum surface rumpling and changes in interlayer distances for the SrPb‐terminated surface of Sr3PbO. However, the calculated surface energies indicate that both SO‐termianted and SrPb‐terminated (001) surfaces of Sr3PbO are energetically feasible, indicating that these surfaces can coexist in a polycrystalline sample of this material. Due to the presence of Pb in Sr3PbO, a comprehensive examination of the electronic structure of bulk and supercell slab structures of Sr3PbO by taking spin–orbit coupling effects into consideration is conducted. Noninsulating nature of electronic structure for the two possible (001) terminations of Sr3PbO is found. The domination of Pb‐6p states at the Fermi energy and the hole screening observed at the SrPb‐terminated surface of Sr3PbO support the p‐type nature observed in the experiment.

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Pushing the detection of cation nonstoichiometry to the limit

Cited by 19 publications

References 64 publications

Epitaxial growth of complex oxide films: Role of surface reconstructions

Epitaxial growth of complex oxide films: Role of surface reconstructions

Identifying Ionic and Electronic Charge Transfer at Oxide Heterointerfaces

Elucidating the Surface Properties of Sr₃PbO Inverse‐Perovskite Topological Insulator: A First‐Principles Study

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Pushing the detection of cation nonstoichiometry to the limit

Cited by 19 publications

References 64 publications

Epitaxial growth of complex oxide films: Role of surface reconstructions

Epitaxial growth of complex oxide films: Role of surface reconstructions

Identifying Ionic and Electronic Charge Transfer at Oxide Heterointerfaces

Elucidating the Surface Properties of Sr3PbO Inverse‐Perovskite Topological Insulator: A First‐Principles Study

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Elucidating the Surface Properties of Sr₃PbO Inverse‐Perovskite Topological Insulator: A First‐Principles Study