Effect of reduced dimensionality on the optical band gap of SrTiO3

Lee, Che-Hui; Podraza, Nikolas J.; Zhu, Ye; Berger, Robert; Shen, S. C.; Sestak, Michelle N.; Collins, R. W.; Kourkoutis, Lena F.; Mundy, Julia A.; Wang, Hui‐Qiong; Mao, Qing; Xi, Xiaoxing; Brillson, L. J.; Neaton, Jeffrey B.; Muller, David A.; Schlom, Darrell G.

doi:10.1063/1.4798241

Cited by 52 publications

(37 citation statements)

References 53 publications

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“…There are some exceptions to this trend, like Sr n+1 Ti n O 3n+1 . Lee et al [37] have recently shown that bandgaps of the Sr n+1 Ti n O 3n+1 Ruddlesden-Popper phase is reduced with an increase of the thickness and we have seen the same effect. In general, these trends could be used to tune the bandgap by increasing or reducing the number of octahedra within the layers.…”

Section: Trends In Stability and Bandgapssupporting

confidence: 83%

Stability and bandgaps of layered perovskites for one- and two-photon water splitting

et al. 2013

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Direct production of hydrogen from water and sunlight requires stable and abundantly available semiconductors with well positioned band edges relative to the water red-ox potentials. We have used density functional theory (DFT) calculations to investigate 300 oxides and oxynitrides in the Ruddlesden-Popper phase of the layered perovskite structure. Based on screening criteria for the stability, bandgaps and band edge positions, we suggest 20 new materials for the light harvesting photo-electrode of a one-photon water splitting device and 5 anode materials for a two-photon device with silicon as photo-cathode. In addition, we explore a simple rule relating the bandgap of the perovskite to the number of octahedra in the layered structure and the B-metal ion. Finally, the quality of the GLLB-SC potential used to obtain the bandgaps, including the derivative discontinuity, is validated against G 0 W 0 @LDA gaps for 20 previously identified oxides and oxynitrides in the cubic perovskite structure.

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Section: Trends In Stability and Bandgapssupporting

confidence: 83%

Stability and bandgaps of layered perovskites for one- and two-photon water splitting

et al. 2013

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“…4(a), in which gaps increase with increasing thickness of the SrTiO 3 region, runs opposite to typical trends in the band gaps of quantum confined systems, as for example previously observed for the Ruddlesden-Popper series Sr n+1 Ti n O 3n+1 . 13 This can be explained by observing that the VBM, the band edge whose energies vary with layering, resides not in the SrTiO 3 region but in the SrFeO 2.5 layer. Therefore, when n is large (i.e., SrTiO 3 regions are less confined), VBM states are actually more confined because SrFeO 2.5 layers are farther apart.…”

Section: -4mentioning

confidence: 99%

“…Past work has explored a variety of routes to tune the band gap and edges of SrTiO 3 , including chemical doping and substitution, [5][6][7][8][9][10][11] epitaxial strain, 12 and quantum confinement. 13 Layered oxide thin films, usually grown by molecular beam epitaxy 14 or pulsed laser deposition, 15 can tune electronic structure via quantum confinement and geometric distortions not found in the bulk components. [16][17][18] Further, control of oxygen vacancies via electrolytic gating has been shown to dramatically and reversibly alter the electronic properties of SrTiO 3 19 and other oxide films.…”

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confidence: 99%

Tuning the electronic structure of SrTiO3/SrFeO3−x superlattices via composition and vacancy control

2014

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Using density functional theory-based calculations, we explore the effects of oxygen vacancies and epitaxial layering on the atomic, magnetic, and electronic structure of (SrTiO3)n(SrFeO3−x)1 superlattices. While structures without oxygen vacancies (x = 0) possess small or non-existent band gaps and ferromagnetic ordering in their iron layers, those with large vacancy concentrations (x = 0.5) have much larger gaps and antiferromagnetic ordering. Though the computed gaps depend numerically on the delicate energetic balance of vacancy ordering and on the value of Hubbard \documentclass[12pt]{minimal}\begin{document}$U_{\textrm {eff}}$\end{document}U eff used in the calculations, we demonstrate that changes in layering can tune the band gaps of these superlattices below that of SrTiO3 (3.2 eV) by raising their valence band maxima. This suggests the possibility that these superlattices could absorb in the solar spectrum, and could serve as water-splitting photocatalysts.

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“…Some alignment of these faults has been observed previously in non-stoichiometric Sr 1þd TiO x samples deposited through source shuttering at 650 C. 34 Of course, deliberately shuttering extra SrO planes into stoichiometric SrTiO 3 is an effective way of introducing RP faults along the growth direction, 24,44 and has been used to make Sr nþ1 Ti n O 3nþ1 phases with n as high as 10. 45 Such a method is not employed, however, in the work described here. Partial orientation of RP faults has also been attributed to composition changes achieved through controlling laser fluence in PLD.…”

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Tuning thermal conductivity in homoepitaxial SrTiO3 films via defects

Brooks

Wilson

Schäfer³

et al. 2015

Applied Physics Letters

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We demonstrate the ability to tune the thermal conductivity of homoepitaxial SrTiO3 films deposited by reactive molecular-beam epitaxy by varying growth temperature, oxidation environment, and cation stoichiometry. Both point defects and planar defects decrease the longitudinal thermal conductivity (k33), with the greatest decrease in films of the same composition observed for films containing planar defects oriented perpendicular to the direction of heat flow. The longitudinal thermal conductivity can be modified by as much as 80%—from 11.5 W m−1K−1 for stoichiometric homoepitaxial SrTiO3 to 2 W m−1K−1 for strontium-rich homoepitaxial Sr1+δTiOx films—by incorporating (SrO)2 Ruddlesden-Popper planar defects.

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Effect of reduced dimensionality on the optical band gap of SrTiO3

Abstract: Atomic and electronic structure of the YBa 2 Cu 3 O 7 / SrTiO 3 interface from first principles

Cited by 52 publications

References 53 publications

Stability and bandgaps of layered perovskites for one- and two-photon water splitting

Stability and bandgaps of layered perovskites for one- and two-photon water splitting

Tuning the electronic structure of SrTiO3/SrFeO3−x superlattices via composition and vacancy control

Tuning thermal conductivity in homoepitaxial SrTiO3 films via defects

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