Recommendation of interstitial hydrogen positions in metal oxides

Tsunoda, Naoki; Kumagai, Yu; Oba, Fumiyasu

doi:10.1016/j.commatsci.2021.111068

Cited by 5 publications

(9 citation statements)

References 66 publications

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“…The 8 Li + ion causes a local structural distortion around the octahedral site; most significantly, it pushes the two nearest neighbour Al ions away, each by 0.22 Å, along the c axis. A recent study of H + interstitials in α-Al 2 O 3 [28] also found the octahedral site to be the only stable interstitial configuration. For Er 3+ ions implanted into α-Al 2 O 3 , 70% were found to occupy octahedral interstitial site, albeit one that is displaced slightly from the ideal octahedral position [29].…”

Section: Resultsmentioning

confidence: 89%

The Site and High Field βNMR Properties of ⁸Li⁺ Implanted in α-Al₂O₃

MacFarlane

Shenton²,

Salman³

et al. 2023

J. Phys.: Conf. Ser.

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We present high (> 2 T) magnetic field βNMR measurements of 8Li+ implanted in single crystals of sapphire, a commonly used backing material for other samples. From the well-resolved quadrupolar splitting, we extract the electric field gradient (EFG) at the implanted 8Li+ site. Comparison with supercell density functional theory calculations of the EFG allows us to identify the octahedral interstitial site as the most likely candidate. In contrast to the zero field βNQR spectra, where multiple singals are detected, only a single site is evident at high field. We discuss possible explanations for this discrepancy. The spin lattice relaxation is extremely slow (1/T 1 < 0.02 s−1 ) over a broad temperature range from 4 to 300 K, demonstrating that cross relaxation with the 27Al nuclear spins is quenched in such high magnetic fields.

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Section: Resultsmentioning

confidence: 89%

The Site and High Field βNMR Properties of ⁸Li⁺ Implanted in α-Al₂O₃

MacFarlane

Shenton²,

Salman³

et al. 2023

J. Phys.: Conf. Ser.

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“…For neutral molecular hydrogen, the ground state is also the

O_o

site with the molecule oriented along the c ‐axis. Finally, based on another approach seeking the interstitial configurations of hydrogen atoms in oxide, especially efficient for protons, Tsunoda 17 confirmed the ground states of each hydrogen state. The formation energy of neutral hydrogen is slightly higher (+0.52 eV) in Allouche's study than in Hodille's.…”

Section: Hydrogen Solubilitymentioning

confidence: 86%

“…A similar value is obtained with the SCAN functional (approximately 7.5 eV). For the band gap energy, this functional is still worse than the HSE06 hybrid functional, which gives more accurate experimental values 16,17 . These values are 30% lower than the experimental value; a well‐known phenomenon due to the fact that DFT is a ground‐state theory which tends to underestimate the value of the experimental band gap, which is equal to 10.6 50,52 or 9.9 eV 51 .…”

Section: Ground‐state Properties Of the Beo Systemmentioning

confidence: 96%

“…and Tsunoda et al. 17 already published results on hydrogen insertion in the BeO system. Allouche studied only neutral hydrogen in its ground state, the

O_o

site.…”

Section: Hydrogen Solubilitymentioning

confidence: 99%

“…Moreover, as regards the solubility of hydrogen isotopes, the only experimental estimate was carried out on sintered beryllium oxide samples loaded with deuterium 13 . Nevertheless, a few theoretical DFT‐based studies investigated the insertion or diffusion properties of hydrogen in the wurtzite structure 14–17 . The recent work of Hodille 15 extends the work of Marinaupoulos et al 16 .…”

Section: Introductionmentioning

confidence: 99%

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Solubility and diffusivity of hydrogen and its isotopes in the BeO system

2023

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This work revisits hydrogen insertion in the wurtzite beryllium oxide in order to fill the gap in scientific knowledge regarding the diffusion coefficients of the different chemical states of hydrogen (neutral, charged, or molecular). Both first‐principle and macroscopic models were used to this end. In the former, two exchange‐correlation functionals (PBE and SCAN) were used to compute the properties of interest and accuracy was then discussed. Regarding the behavior of interstitial insertion of hydrogen, this work is slightly different from previous works; hydrogen was mainly found in the form of charged H− or H+ ions, depending on experimental conditions. In regard to diffusivity properties, a complex migration pathway was found for hydrogen cation. Finally, the present study succeeded in producing a reliable set of diffusion coefficients for neutral, charged, and molecular hydrogen.

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Exploring Intrinsic and Extrinsic p-Type Dopability of Atomically Thin β-TeO₂ from First Principles

Costa-Amaral,

Bae,

et al. 2024

ACS Appl. Mater. Interfaces

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Two-dimensional (2D) β-TeO 2 has gained attention as a promising material for optoelectronic and power device applications, thanks to its transparency and high hole mobility. However, the mechanisms driving its p-type conductivity and dopability remain elusive. In this study, we investigate the intrinsic and extrinsic point defects in monolayer and bilayer β-TeO 2 , the latter of which has been experimentally synthesized, using the Heyd−Scuseria−Ernzerhof (HSE) + D3 hybrid functional. Our results reveal that most intrinsic defects are unlikely to contribute to p-type doping in 2D β-TeO 2 . Moreover, Si and H contamination could further impair p-type conductivity. Since the point defects do not contribute to p-type conductivity, we suggest two possible mechanisms for hole conduction: hopping conduction via localized impurity states, and substrate effects. We also explored substitutional p-type doping in 2D β-TeO 2 with 10 trivalent elements. Among these, the Bi dopant is found to exhibit a relatively shallow acceptor transition level. However, all the dopants introduce deep localized states, where hole polarons are trapped by the lone pairs of Te atoms. Interestingly, monolayer β-TeO 2 shows potential advantages over bilayers due to reduced self-compensation effects for p-type dopants. These findings provide valuable insights into defect engineering strategies for future electronic applications involving 2D β-TeO 2 .

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Recommendation of interstitial hydrogen positions in metal oxides

Cited by 5 publications

References 66 publications

The Site and High Field βNMR Properties of ⁸Li⁺ Implanted in α-Al₂O₃

The Site and High Field βNMR Properties of ⁸Li⁺ Implanted in α-Al₂O₃

Solubility and diffusivity of hydrogen and its isotopes in the BeO system

Exploring Intrinsic and Extrinsic p-Type Dopability of Atomically Thin β-TeO₂ from First Principles

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Recommendation of interstitial hydrogen positions in metal oxides

Cited by 5 publications

References 66 publications

The Site and High Field βNMR Properties of 8Li+ Implanted in α-Al2O3

The Site and High Field βNMR Properties of 8Li+ Implanted in α-Al2O3

Solubility and diffusivity of hydrogen and its isotopes in the BeO system

Exploring Intrinsic and Extrinsic p-Type Dopability of Atomically Thin β-TeO2 from First Principles

Contact Info

Product

Resources

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The Site and High Field βNMR Properties of ⁸Li⁺ Implanted in α-Al₂O₃

The Site and High Field βNMR Properties of ⁸Li⁺ Implanted in α-Al₂O₃

Exploring Intrinsic and Extrinsic p-Type Dopability of Atomically Thin β-TeO₂ from First Principles