Distinct behaviour of localized and delocalized carriers in anatase TiO2 (001) during reaction with O2

C Bigi; Z Tang; G Pierantozzi; P Orgiani; P Das; J Fujii; I Vobornik; T Pincelli; A Troglia; T Lee; R Ciancio; G Drazic; A Verdini; A Regoutz; Phil King; Deepnarayan Biswas; G Rossi; G Panaccione; A Selloni

doi:10.1103/PhysRevMaterials.4.025801

Distinct behaviour of localized and delocalized carriers in anatase TiO₂ (001) during reaction with O₂

C Bigi, Z Tang, G Pierantozzi, P Orgiani, P Das, J Fujii, I Vobornik, T Pincelli, A Troglia, T Lee, R Ciancio, G Drazic, A Verdini, A Regoutz, Phil King, Deepnarayan Biswas, G Rossi, G Panaccione, A Selloni

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Abstract

Two-dimensional (2D) metallic states induced by oxygen vacancies (V_Os) at oxide surfaces and interfaces provide opportunities for the development of advanced applications, but the ability to control the behavior of these states is still limited. We used angle resolved photoelectron spectroscopy combined with density-functional theory (DFT) to study the reactivity of V_O-induced states at the (001) surface of anatase TiO₂, where both 2D metallic and deeper lying in-gap states (IGs) are observed. The 2D and IG states exhibit remarkably different evolutions when the surface is exposed to molecular O₂: while IGs are almost completely quenched, the metallic states are only weakly affected. DFT calculations indeed show that the IGs originate from surface V_Os and remain localized at the surface, where they can promptly react with O₂. In contrast, the metallic states originate from subsurface vacancies whose migration to the surface for recombination with O₂ is kinetically hindered on anatase TiO₂ (001), thus making them much less sensitive to oxygen dosing.

Original language	English
Article number	025801
Number of pages	9
Journal	Physical Review Materials
Volume	4
Issue number	2
DOIs	https://doi.org/10.1103/PhysRevMaterials.4.025801
Publication status	Published - 28 Feb 2020

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Copyright © 2020 American Physical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1103/PhysRevMaterials.4.025801
Accepted author manuscript, 7.16 MB

RS Phil King: Electronic Structure Engineering of Novel Topological Phases
King, P. (PI)
1/10/18 → 30/09/21
Project: Fellowship

Distinct behaviour of localised and delocalised carriers in anatase TiO2 (001) during reaction with O2 (dataset)
Bigi, C. (Creator), Tang, Z. (Creator), Pierantozzi, G. (Creator), Orgiani, P. (Creator), Das, P. (Creator), Fujii, J. (Creator), Vobornik, I. (Creator), Pincelli, T. (Creator), Troglia, A. (Creator), Lee, T. (Creator), Ciancio, R. (Creator), Drazic, G. (Creator), Verdini, A. (Creator), Regoutz, A. (Creator), King, P. (Creator), Biswas, D. (Creator), Rossi, G. (Creator), Panaccione, G. (Creator) & Selloni, A. (Creator), University of St Andrews, 8 Jul 2020
DOI: 10.17630/c47e8589-c2a7-4af2-80d9-feaf1b546134
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Bigi, C., Tang, Z., Pierantozzi, G., Orgiani, P., Das, P., Fujii, J., Vobornik, I., Pincelli, T., Troglia, A., Lee, T., Ciancio, R., Drazic, G., Verdini, A., Regoutz, A., King, P., Biswas, D., Rossi, G., Panaccione, G., & Selloni, A. (2020). Distinct behaviour of localized and delocalized carriers in anatase TiO₂ (001) during reaction with O₂. Physical Review Materials, 4(2), Article 025801. https://doi.org/10.1103/PhysRevMaterials.4.025801

@article{89934390221344b89de512bad756ee18,

title = "Distinct behaviour of localized and delocalized carriers in anatase TiO2 (001) during reaction with O2",

abstract = "Two-dimensional (2D) metallic states induced by oxygen vacancies (VOs) at oxide surfaces and interfaces provide opportunities for the development of advanced applications, but the ability to control the behavior of these states is still limited. We used angle resolved photoelectron spectroscopy combined with density-functional theory (DFT) to study the reactivity of VO-induced states at the (001) surface of anatase TiO2, where both 2D metallic and deeper lying in-gap states (IGs) are observed. The 2D and IG states exhibit remarkably different evolutions when the surface is exposed to molecular O2: while IGs are almost completely quenched, the metallic states are only weakly affected. DFT calculations indeed show that the IGs originate from surface VOs and remain localized at the surface, where they can promptly react with O2. In contrast, the metallic states originate from subsurface vacancies whose migration to the surface for recombination with O2 is kinetically hindered on anatase TiO2 (001), thus making them much less sensitive to oxygen dosing.",

author = "C Bigi and Z Tang and G Pierantozzi and P Orgiani and P Das and J Fujii and I Vobornik and T Pincelli and A Troglia and T Lee and R Ciancio and G Drazic and A Verdini and A Regoutz and Phil King and Deepnarayan Biswas and G Rossi and G Panaccione and A Selloni",

year = "2020",

month = feb,

day = "28",

doi = "10.1103/PhysRevMaterials.4.025801",

language = "English",

volume = "4",

journal = "Physical Review Materials",

issn = "2475-9953",

publisher = "American Physical Society",

number = "2",

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Bigi, C, Tang, Z, Pierantozzi, G, Orgiani, P, Das, P, Fujii, J, Vobornik, I, Pincelli, T, Troglia, A, Lee, T, Ciancio, R, Drazic, G, Verdini, A, Regoutz, A, King, P, Biswas, D, Rossi, G, Panaccione, G & Selloni, A 2020, 'Distinct behaviour of localized and delocalized carriers in anatase TiO₂ (001) during reaction with O₂', Physical Review Materials, vol. 4, no. 2, 025801. https://doi.org/10.1103/PhysRevMaterials.4.025801

TY - JOUR

T1 - Distinct behaviour of localized and delocalized carriers in anatase TiO2 (001) during reaction with O2

AU - Bigi, C

AU - Tang, Z

AU - Pierantozzi, G

AU - Orgiani, P

AU - Das, P

AU - Fujii, J

AU - Vobornik, I

AU - Pincelli, T

AU - Troglia, A

AU - Lee, T

AU - Ciancio, R

AU - Drazic, G

AU - Verdini, A

AU - Regoutz, A

AU - King, Phil

AU - Biswas, Deepnarayan

AU - Rossi, G

AU - Panaccione, G

AU - Selloni, A

PY - 2020/2/28

Y1 - 2020/2/28

N2 - Two-dimensional (2D) metallic states induced by oxygen vacancies (VOs) at oxide surfaces and interfaces provide opportunities for the development of advanced applications, but the ability to control the behavior of these states is still limited. We used angle resolved photoelectron spectroscopy combined with density-functional theory (DFT) to study the reactivity of VO-induced states at the (001) surface of anatase TiO2, where both 2D metallic and deeper lying in-gap states (IGs) are observed. The 2D and IG states exhibit remarkably different evolutions when the surface is exposed to molecular O2: while IGs are almost completely quenched, the metallic states are only weakly affected. DFT calculations indeed show that the IGs originate from surface VOs and remain localized at the surface, where they can promptly react with O2. In contrast, the metallic states originate from subsurface vacancies whose migration to the surface for recombination with O2 is kinetically hindered on anatase TiO2 (001), thus making them much less sensitive to oxygen dosing.

AB - Two-dimensional (2D) metallic states induced by oxygen vacancies (VOs) at oxide surfaces and interfaces provide opportunities for the development of advanced applications, but the ability to control the behavior of these states is still limited. We used angle resolved photoelectron spectroscopy combined with density-functional theory (DFT) to study the reactivity of VO-induced states at the (001) surface of anatase TiO2, where both 2D metallic and deeper lying in-gap states (IGs) are observed. The 2D and IG states exhibit remarkably different evolutions when the surface is exposed to molecular O2: while IGs are almost completely quenched, the metallic states are only weakly affected. DFT calculations indeed show that the IGs originate from surface VOs and remain localized at the surface, where they can promptly react with O2. In contrast, the metallic states originate from subsurface vacancies whose migration to the surface for recombination with O2 is kinetically hindered on anatase TiO2 (001), thus making them much less sensitive to oxygen dosing.

U2 - 10.1103/PhysRevMaterials.4.025801

DO - 10.1103/PhysRevMaterials.4.025801

M3 - Article

SN - 2475-9953

VL - 4

JO - Physical Review Materials

JF - Physical Review Materials

IS - 2

M1 - 025801

ER -

Distinct behaviour of localized and delocalized carriers in anatase TiO2 (001) during reaction with O2

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Distinct behaviour of localised and delocalised carriers in anatase TiO2 (001) during reaction with O2 (dataset)

Cite this

Distinct behaviour of localized and delocalized carriers in anatase TiO₂ (001) during reaction with O₂