Electric-field-driven octahedral rotation in perovskite

Kyung, Wonshik; Kim, Choong Hyun; Kim, Yeong Kwan; Kim, Beomyoung; Kim, Chul; Jung, Woo‐Bin; Kwon, Junyoung; Kim, Min‐Soo; Bostwick, Aaron; Denlinger, Jonathan D.; Yoshida, Yoshiyuki

doi:10.1038/s41535-020-00306-1

Cited by 10 publications

(8 citation statements)

References 40 publications

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“…63 For the piezoelectric coupling, piezoelectricity is normally symmetry forbidden in room temperature STO because it is centrosymmetric, but the recent discovery of a surface piezoelectric effect induced by interfacial electric fields (i.e., electrostriction) 64 and surface relaxation 65 indicates that such an effect is present, possibly to a large extent, at the STO/ water interface. It is also worth noting that such a surface piezoelectric effect has been associated with perovskite octahedra rotation, 66 which could reduce the effects of strain on OER activity. 21 Other than deformations directly associated with the hole polaron, 43 changes in free carrier concentrations can also contribute to interfacial strain.…”

Section: Discussionmentioning

confidence: 99%

Coherent Acoustic Interferometry during the Photodriven Oxygen Evolution Reaction Associates Strain Fields with the Reactive Oxygen Intermediate (Ti–OH*)

et al. 2021

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The oxygen evolution reaction (OER) from water requires the formation of metastable, reactive oxygen intermediates to enable oxygen–oxygen bond formation. Conversely, such reactive intermediates could also structurally modify the catalyst. A descriptor for the overall catalytic activity, the first electron and proton transfer OER intermediate from water, (M–OH*), has been associated with significant distortions of the metal–oxygen bonds upon charge-trapping. Time-resolved spectroscopy of in situ, photodriven OER on transition metal oxide surfaces has characterized M–OH* for the charge trapping and the symmetry of the lattice distortions by optical and vibrational transitions, respectively, but had yet to detect an interfacial strain field arising from a surface coverage M–OH*. Here, we utilize picosecond, coherent acoustic interferometry to detect the uniaxial strain normal to the SrTiO3/aqueous interface directly caused by Ti–OH*. The spectral analysis applies a fairly general methodology for detecting a combination of the spatial extent, magnitude, and generation time of the interfacial strain through the coherent oscillations’ phase. For lightly n-doped SrTiO3, we identify the strain generation time (1.31 ps), which occurs simultaneously with Ti–OH* formation, and a tensile strain of 0.06% (upper limit 0.6%). In addition to fully characterizing this intermediate across visible, mid-infrared, and now GHz-THz probes on SrTiO3, we show that strain fields occur with the creation of some M–OH*, which modifies design strategies for tuning catalytic activity and provides insight into photo-induced degradation so prevalent for OER. To that end, the work put forth here provides a unique methodology to characterize intermediate-induced interfacial strain across OER catalysts.

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Section: Discussionmentioning

confidence: 99%

Coherent Acoustic Interferometry during the Photodriven Oxygen Evolution Reaction Associates Strain Fields with the Reactive Oxygen Intermediate (Ti–OH*)

et al. 2021

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“…At the electric fields studied in bulk, we are very far from the insulating-metal transition. As a consequence of the volume changes under the electric field, there will also be changes in the octahedral rotations [ 54 ] that we do not analyze here.…”

Section: Resultsmentioning

confidence: 99%

Mott Insulator Ca2RuO4 under External Electric Field

Cuono¹,

Autieri²

2022

Materials

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We have investigated the structural, electronic and magnetic properties of the Mott insulator Ca2RuO4 under the application of a static external electric field in two regimes: bulk systems at small fields and thin films at large electric fields. Ca2RuO4 presents S- and L-Pbca phases with short and long c lattice constants and with large and small band gaps, respectively. Using density functional perturbation theory, we have calculated the Born effective charges as response functions. Once we break the inversion symmetry by off-centering the Ru atoms, we calculate the piezoelectric properties of the system that suggest an elongation of the system under an electric field. Finally, we investigated a four-unit cell slab in larger electric fields, and we found insulator–metal transitions induced by the electric field. By looking at the local density of states, we have found that the gap gets closed on surface layers while the rest of the sample is insulating. Correlated to the electric-field-driven gap closure, there is an increase in the lattice constant c. Regarding the magnetic properties, we have identified two phase transitions in the magnetic moments with one surface that gets completely demagnetized at the largest field investigated. In all cases, the static electric field increases the lattice constant c and reduces the band gap of Ca2RuO4, playing a role in the competition between the L-phase and the S-phase.

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“…This may come from the following reasons. For the case of ARPES measurements, charge doping from K atoms is confined to a few surface layers [ 44 ] and ARPES probes only the doped layers due to its surface sensitivity [ 49 ] (see Supporting Information for ARPES data regarding K dosing of a thicker SRO film and detailed discussion on surface sensitivity of AMD and ARPES). On the other hand, the measured Hall effect is averaged over the entire thickness of the film in ionic‐liquid gating experiments, resulting in weakened gating effects.…”

Section: Discussionmentioning

confidence: 99%

“…However, a key difference is the amount of induced charges. The electric field produced by the alkali metal on the SrO surface is of the order 1 V Å −1 , [44] while the electric field produced by liquid gating is of the order 0.1 V Å −1 . [36,45,46] Thus, the AMD method should induce an order of magnitude more charge carriers into the system compared to the ionic-liquid gating method, which would result in a significantly larger change in E F (see Supporting Information for detailed quantitative analysis).…”

Section: R N E H N E H N E H H Hmentioning

confidence: 99%

Electric Control of 2D Van Hove Singularity in Oxide Ultra‐Thin Films

Kim

Sohn

et al. 2023

Advanced Materials

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Divergent density of states (DOS) can induce extraordinary phenomena such as significant enhancement of superconductivity and unexpected phase transitions. Moreover, van Hove singularities (VHSs) are known to lead to divergent DOS in two-dimensional (2D) systems. Despite the recent interest in VHSs, only a few controllable cases have been reported to date. In this work, we investigate the electronic band structures of a 2D VHS with angle-resolved photoemission spectroscopy and control transport properties by utilizing an atomically ultrathin SrRuO3 film. By applying electric fields with alkali metal deposition and ionic-liquid gating methods, we precisely control the 2D VHS, and the sign of the charge carrier. Use of a tunable 2D VHS in an atomically flat oxide film could serve as a new strategy to realize infinite DOS near the Fermi level, thereby allowing efficient tuning of electric properties.

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Electric-field-driven octahedral rotation in perovskite

Cited by 10 publications

References 40 publications

Coherent Acoustic Interferometry during the Photodriven Oxygen Evolution Reaction Associates Strain Fields with the Reactive Oxygen Intermediate (Ti–OH*)

Coherent Acoustic Interferometry during the Photodriven Oxygen Evolution Reaction Associates Strain Fields with the Reactive Oxygen Intermediate (Ti–OH*)

Mott Insulator Ca2RuO4 under External Electric Field

Electric Control of 2D Van Hove Singularity in Oxide Ultra‐Thin Films

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