Quantitative theory of the oxygen vacancy and carrier self-trapping in bulk TiO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>

Deák, Péter; Aradi, Bálint; Frauenheim, Thomas

doi:10.1103/physrevb.86.195206

Cited by 177 publications

(148 citation statements)

References 64 publications

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“…Recently, DFT methods beyond conventional DFT, specifically the LDA+U method 14 as well as hybrid functionals 15 , have been used to study TiO 2 , yielding in general satisfactory results. 7,16,17 For example, the experimental band gap of pristine TiO 2 is reproduced, and the relative stability of various vacancy charge states and the location of defect states in the band gap also agree well with experiments.…”

Section: Introductionsupporting

confidence: 65%

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

et al. 2015

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Understanding electronic properties of sub-stoichiometric phases of titanium oxide such as Magnéli phase Ti 4 O 7 is crucial in designing and modeling resistive switching devices. Here we present our study on Magnéli phase Ti 4 O 7 together with rutile TiO 2 and Ti 2 O 3 using density functional theory methods with atomic-orbital-based self-interaction correction (ASIC). We predict a new antiferromagnetic ground state in the low temperature phase (or LT phase), and we explain energy difference with a competing antiferromagnetic state using a Heisenberg model. The predicted energy ordering of these states in the LT phase is calculated to be robust in a wide range of modeled isotropic strain. We have also investigated the dependence of the electronic structures of the Ti-O phases on stoichiometry. The splitting of titanium t 2g orbitals is enhanced with increasing oxygen deficiency as Ti-O is reduced. The electronic properties of all these phases can be reasonably well described by applying ASIC with a 'standard' value for transition metal oxides of the empirical parameter α of 0.5 representing the magnitude of the applied self-interaction correction.

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Section: Introductionsupporting

confidence: 65%

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

et al. 2015

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“…15,[60][61][62][63] These effects should be taken into consid-eration when explaining the observable properties of all TiO 2 polymorphs.…”

Section: Beyond Bulk Energy Levelsmentioning

confidence: 99%

“…When calculating I using the ∆SCF approach, the BB1k functional accounts for the self-interaction error, 16 while when calculating E g the HSE06 functional describes well the periodic solid, and indeed is known to reproduce accurately the band gaps of rutile and anatase. 61 The plane-wave DFT calculations were performed using the VASP code, [80][81][82][83] with the projector augmented wave approach 84 used to describe the interaction between the core …”

Section: Periodic Models Of the Ideal Solidmentioning

confidence: 99%

Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

et al. 2015

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We report that the valence and conduction band energies of TiO 2 can be tuned over a 4 eV range by varying the local coordination environments of Ti and O. We examine the electronic structure of eight known polymorphs and align their ionization potential and electron affinity relative to an absolute energy reference, using an accurate multi-scale quantum-chemical approach. For applications in photocatalysis, we identify the optimal combination of phases to enhance activity in the visible spectrum. The results provide a coherent explanation for a wide range of phenomena, including the performance of TiO 2 as an anode material for Li-ion batteries, allow us to pinpoint hollandite TiO 2 as a new candidate transparent conducting oxide, and serve as a guide to improving the efficiency of photoelectrochemical water splitting through polymorph engineering of TiO 2 .

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“…Hence, they cannot directly be used complementarily in identifying defects. 19,20,23,24 This can, for example, be observed in the case of H i : Conductivity, transport, electron paramagnetic resonance, and infrared absorption measurements report on a shallow donor level with thermal transition energies of several meV, 10,11,25,[30][31][32] while absorption data indicate optical transition energies of around 1-2 eV. 8,28,32,33 Another prominent example is V O .…”

Section: Introductionmentioning

confidence: 99%

“…[19][20][21][22][23][24][25][26][27][28][29] First, this makes the theoretical description of defects in rutile TiO 2 exceptionally challenging. 19,24 Second, polaronic effects can also lead to different defects having similar experimental signatures as electrons are trapped at similar Ti sites no matter which defect they actually originate from. 19 Another consequence of the polaronic effects is that techniques which probe thermal or optical transition energies will yield significantly different values for the same defect.…”

Section: Introductionmentioning

confidence: 99%

Influence of annealing atmosphere on formation of electrically-active defects in rutile TiO2

Zimmermann

Bonkerud

Herklotz

et al. 2018

Journal of Applied Physics

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Electronic states in the upper part of the bandgap of reduced and/or hydrogenated n-type rutile TiO2 single crystals have been studied by means of thermal admittance and deep-level transient spectroscopy measurements. The studies were performed at sample temperatures between 28 and 300 K. The results reveal limited charge carrier freeze-out even at 28 K and evidence the existence of dominant shallow donors with ionization energies below 25 meV. Interstitial atomic hydrogen is considered to be a major contributor to these shallow donors, substantiated by infrared absorption measurements. Three defect energy levels with positions of about 70 meV, 95 meV, and 120 meV below the conduction band edge occur in all the studied samples, irrespective of the sample production batch and the post-growth heat treatment used. The origin of these levels is discussed in terms of electron polarons, intrinsic point defects, and/or common residual impurities, where especially interstitial titanium atoms, oxygen vacancies, and complexes involving Al atoms appear as likely candidates. In contrast, no common deep-level defect, exhibiting a charge state transition in the 200–700 meV range below the conduction band edge, is found in different samples. This may possibly indicate a strong influence on deep-level defects by the post-growth heat treatments employed.

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Quantitative theory of the oxygen vacancy and carrier self-trapping in bulk TiO2

Cited by 177 publications

References 64 publications

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

Influence of annealing atmosphere on formation of electrically-active defects in rutile TiO2

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Quantitative theory of the oxygen vacancy and carrier self-trapping in bulk TiO2

Cited by 177 publications

References 64 publications

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

Polymorph Engineering of TiO2: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination

Influence of annealing atmosphere on formation of electrically-active defects in rutile TiO2

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Polymorph Engineering of TiO₂: Demonstrating How Absolute Reference Potentials Are Determined by Local Coordination