First-principles embedded-cluster calculations of the neutral and charged oxygen vacancy at the rutile<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">TiO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>(110) surface

Berger, Daniel; Oberhofer, Harald; Reuter, Karsten

doi:10.1103/physrevb.92.075308

Cited by 27 publications

(36 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…O atoms are removed in the form of O 2 molecules; this leaves two extra electrons per O atom in a t 2g defect band with a maximum density at ∼0.9 eV below the E F [82]. The broad defect density extends up to E F , which is ∼0.1 eV below the conduction-band minimum (CBM) [41,42,47,48]. Whether these electrons remain localized at Ti 3+ sites where the Ti-O bonds are broken, or are localized near the vacancies in polaron states, is under debate [42,[83][84][85].…”

Section: Methodsmentioning

confidence: 99%

“…e-p Interactions are most vividly manifested in temperature dependence of the optical properties of solid-state materials, and thus constitute a well-defined target for incisive comparisons between experiment and theory. In addition to the optical properties, e-p interactions also affect the carrier transport, which is crucially important for electron correlation and photocatalysis, but is also difficult to relate to the specific electronic structures of materials [41][42][43]. Here we focus on the temperature dependence of the electronic bands, from the first-principles understanding of e-p interactions that affect the relevant atomic orbitals, and how they are manifested in the optical properties of materials.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electron-phonon coupling in d -electron solids: A temperature-dependent study of rutile TiO2 by first-principles theory and two-photon photoemission

Shang

Argondizzo

Tan

et al. 2019

Phys. Rev. Research

View full text Add to dashboard Cite

is a paradigmatic transition-metal oxide with applications in optics, electronics, photocatalysis, etc., that are subject to pervasive electron-phonon interaction. To understand how energies of its electronic bands, and in general semiconductors or metals where the frontier orbitals have a strong d-band character, depend on temperature, we perform a comprehensive theoretical and experimental study of the effects of electron-phonon (e-p) interactions. In a two-photon photoemission (2PP) spectroscopy study we observe an unusual temperature dependence of electronic band energies within the conduction band of reduced rutile TiO 2 , which is contrary to the well-understood sp-band semiconductors and points to a so far unexplained dichotomy in how the e-p interactions affect differently the materials where the frontier orbitals are derived from the sp-and d orbitals. To develop a broadly applicable model, we employ state-of-the-art first-principles calculations that explain how phonons promote interactions between the Ti-3d orbitals of the conduction band within the octahedral crystal field. The characteristic difference in e-p interactions experienced by the Ti-3d orbitals of rutile TiO 2 crystal lattice are contrasted with the more familiar behavior of the Si-2s orbitals of stishovite SiO 2 polymorph, in which the frontier 2s orbital experiences a similar crystal field with the opposite effect. The findings of this analysis of how e-p interactions affect the d-and sp-orbital derived bands can be generally applied to related materials in a crystal field. The calculated temperature dependence of d-orbital derived band energies agrees well with and explains the temperature-dependent inter-d-band transitions recorded in 2PP spectroscopy of TiO 2. The general understanding of how e-p interactions affect d-orbital derived bands is likely to impact the understanding of temperature-dependent properties of highly correlated materials.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electron-phonon coupling in d -electron solids: A temperature-dependent study of rutile TiO2 by first-principles theory and two-photon photoemission

Shang

Argondizzo

Tan

et al. 2019

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…[4][5][6][7] Small polarons play a decisive role in electron transport, 8,9 optical absorption, and chemical reactivity, and have crucial implications in other diverse phenomena including high-T c superconductivity, 10 colossal magnetoresistance, 11,12 thermoelectricity, 13 photoemission, 14 and photochemistry. 15 Here we focus on the (110) surface of rutile TiO 2 , TiO 2 (110), a highly studied oxide surface 16 for which the presence of small polarons was predicted by different computational approaches [17][18][19][20] and confirmed by several experiments. [21][22][23] Excess electrons are found to orig-inate mostly from surface defects, such as oxygen vacancies, Nb impurities, hydroxyl groups and interstitial titanium atoms.…”

Section: Introductionmentioning

confidence: 95%

Formation and dynamics of small polarons on the rutile TiO2 (110) surface

et al. 2018

View full text Add to dashboard Cite

Charge trapping and formation of polarons is a pervasive phenomenon in transition metal oxide compounds, in particular at the surface, affecting fundamental physical properties and functionalities of the hosting materials. Here we investigate via first-principle techniques the formation and dynamics of small polarons on the reduced surface of titanium dioxide, an archetypal system for polarons, for a wide range of oxygen vacancy concentrations. We report how the essential features of polarons can be adequately accounted in terms of few quantities: the local structural and chemical environment, the attractive interaction between negatively charged polarons and positively charged oxygen vacancies, and the spin-dependent polaron-polaron Coulomb repulsion. We combined molecular dynamics simulations on realistic samples derived from experimental observations with simplified static models, aiming to disentangle the various variables at play. We find that depending on the specific trapping site, different types of polarons can be formed, with distinct orbital symmetries and different degree of localization and structural distortion. The energetically most stable polaron site is the subsurface Ti atom below the undercoordinated surface Ti atom, owing to a small energy cost to distort the lattice and a suitable electrostatic potential. Polaron-polaron repulsion and polaron-vacancy attraction determine the spatial distribution of polarons as well as the energy of the polaronic in-gap state. In the range of experimentally reachable oxygen vacancy concentrations the calculated data are in excellent agreement with observations, thus validating the overall interpretation.arXiv:1805.01849v1 [cond-mat.mtrl-sci]

show abstract

“…This approach builds upon the earlier work of (Norgett, 1971), who modelled a vacancy in binary metal oxides using a set of Gaussian basis functions to describe the wave function, embedded within a lattice of polarisable ions represented by point charges. The boundary conditions allow one to access an absolute reference energy, from which ionisation energies can be calculated consistently (see Section 3.1), while two-dimensional (Berger et al, 2014;Berger et al, 2015;Downing et al, 2014a, b;Dutta et al, 2012;Goumans et al, 2008;Herschend et al, 2004;Keal et al, 2011;Logsdail et al, 2016;Sokol et al, 2004;Stefanovich and Truong, 1997) and one-dimensional (Buckeridge et al, 2013;Oliva et al, 2008) systems pose no significant problems to the technique.…”

Section: Modelling Point Defects With Hybrid Quantum Mechanical / Molmentioning

confidence: 99%

Quantum Mechanical/Molecular Mechanical (QM/MM) Approaches

Catlow

Buckeridge

Farrow

et al. 2017

Handbook of Solid State Chemistry

View full text Add to dashboard Cite

Computational modeling techniques are now standard tools in solid‐state science. They are used routinely to model and predict structures, to investigate defect, transport, and spectroscopic properties of solids, to simulate sorption and diffusion, to develop models for nucleation and growth of solids, and increasingly to model and predict reaction mechanisms. They are applied to bulk solids, surfaces, and nanostructures, and successful applications are reported for all major classes of solid: metals, semiconductors, inorganic and ceramic materials, and molecular crystals. Modeling methods are now indeed tools that are used to guide, interpret, and predict experiment.

show abstract

First-principles embedded-cluster calculations of the neutral and charged oxygen vacancy at the rutileTiO2(110) surface

Cited by 27 publications

References 76 publications

Electron-phonon coupling in d -electron solids: A temperature-dependent study of rutile TiO2 by first-principles theory and two-photon photoemission

Electron-phonon coupling in d -electron solids: A temperature-dependent study of rutile TiO2 by first-principles theory and two-photon photoemission

Formation and dynamics of small polarons on the rutile TiO2 (110) surface

Quantum Mechanical/Molecular Mechanical (QM/MM) Approaches

Contact Info

Product

Resources

About