Photoinduced insulator-to-metal transition and coherent acoustic phonon propagation in 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">LaCoO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>
 thin films explored by femtosecond pump-probe ellipsometry

Zahradník, Martin; Kiaba, M.; Espinoza, Shirly; Rębarz, Mateusz; Andreasson, Jakob; Caha, Ondřej; Abadizaman, Farzin; Munzar, Dominik; Dubroka, Adam

doi:10.1103/physrevb.105.235113

Cited by 6 publications

(3 citation statements)

References 40 publications

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Section: Discussionmentioning

confidence: 99%

“…It is very plausible that the coherent acoustic phonons are generated (especially at a few atomic layers in the substrate nearby the interface) and detected in the substrates (Figure S9 , Supporting Information). The penetration depth of LaCoO 3 is reported to be 110 nm, [ 44 ] which allows for the prominent transmission through a 40 nm thick thin film. In such a scenario, the pump pulse generates a transient thermal strain, producing longitudinal temperature gradients that spread at the interface between the film and substrate to generate the coherent acoustic phonon.…”

Section: Discussionmentioning

confidence: 99%

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Separated Electron–Phonon and Phonon–Phonon Scatterings Across Interface in Thin Film LaCoO₃/SrTiO₃

Hao,

Gu,

Tian

et al. 2023

Advanced Science

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Electron–phonon coupling (EPC) and phonon–phonon scattering (PPS) are at the core of the microscopic physics mechanisms of vast quantum materials. However, to date, there are rarely reports that these two processes can be spatially separated, although they are usually temporally detached with different characteristic lifetimes. Here, by employing ultrafast spectroscopy to investigate the photo‐carrier ultrafast dynamics in a LaCoO3 thin film on a (100) SrTiO3 substrate, intriguing evidence is found that the two interactions are indeed spatially separated. The EPC mainly occurs in the thin film, whereas PPS is largely in the substrate, especially at the several atomic layers near the interface. Across‐interface penetration and decay of optical phonons into acoustic phonons thus naturally occur. An EPC strength λEg = 0.30 is also obtained and an acoustic phonon mode at 45.3 GHz is observed. The finding lays out a cornerstone for future quantum nano device designs.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Separated Electron–Phonon and Phonon–Phonon Scatterings Across Interface in Thin Film LaCoO₃/SrTiO₃

Hao,

Gu,

Tian

et al. 2023

Advanced Science

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“…TSE can be also applied to study various properties of optoelectronic materials like Si, Ge, InP, GaP, ZnO, GaN,and perovskite oxides. [286,[289][290][291][292][293] After exciting a semiconductor with a highintense laser beam, electrons and holes will occupy CB and VB band states, respectively. This will immediately, within some fs, cause bandgap renormalization (BGR) as expressed in the redshift of transition energies between VB and CB.…”

Section: Pv-related Electron Dynamicsmentioning

confidence: 99%

Integration of Multijunction Absorbers and Catalysts for Efficient Solar‐Driven Artificial Leaf Structures: A Physical and Materials Science Perspective

Hannappel,

Shekarabi,

Jaegermann

et al. 2024

Solar RRL

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Artificial leaves could be the breakthrough technology to overcome the limitations of storage and mobility through the synthesis of chemical fuels from sunlight, which will be an essential component of a sustainable future energy system. However, the realization of efficient solar‐driven artificial leaf structures requires integrated specialized materials such as semiconductor absorbers, catalysts, interfacial passivation, and contact layers. To date, no competitive system has emerged due to a lack of scientific understanding, knowledge‐based design rules, and scalable engineering strategies. Here, we will discuss competitive artificial leaf devices for water splitting, focusing on multi‐absorber structures to achieve solar‐to‐hydrogen conversion efficiencies exceeding 15%. A key challenge is integrating photovoltaic and electrochemical functionalities in a single device. Additionally, optimal electrocatalysts for intermittent operation at photocurrent densities of 10‐20 mA cm‐2 must be immobilized on the absorbers with specifically designed interfacial passivation and contact layers, so‐called buried junctions. This minimizes voltage and current losses and prevents corrosive side reactions. Key challenges include understanding elementary steps, identifying suitable materials, and developing synthesis and processing techniques for all integrated components. This is crucial for efficient, robust, and scalable devices. Here, we discuss and report on corresponding research efforts to produce green hydrogen with unassisted solar‐driven (photo‐)electrochemical devices.This article is protected by copyright. All rights reserved.

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Ultrafast Dynamic Terahertz Response of Ti₂O₃ Film during Photoinduced Metal–Insulator Transition

Cai

Zhu

et al. 2022

J. Phys. Chem. C

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Ti2O3 with an ultranarrow bandgap of 0.1 eV, exhibiting an intriguing thermally induced metal–insulator transition (MIT), has drawn significant attention in photothermal conversion, photocatalysts, and mid-infrared photodetection. However, the ultrafast photoexcitation dynamics of Ti2O3 film and whether the laser excitation can trigger the MIT of Ti2O3 were rarely discussed. Here, a typical time-resolved optical pump terahertz probe (OPTP) spectroscopy was used to investigate the ultrafast terahertz response of Ti2O3 film excited by a femtosecond laser. We found that a transient photoinduced carrier generation process occurred within 4 ps. A fast relaxation with a time constant of approximately 2 ps followed, which can be attributed to the recombination of the photogenerated carriers. Subsequently, a slow transition process was observed after the fast recovery process, and this phenomenon can be ascribed to the ultrafast photothermal conversion through nonradiative relaxation. Our work will provide new sights for investigating MIT characteristics of Ti2O3 and open a route toward achieving ultrafast dynamic modulation optoelectronics operating in the terahertz regime.

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Photoinduced insulator-to-metal transition and coherent acoustic phonon propagation in LaCoO3 thin films explored by femtosecond pump-probe ellipsometry

Cited by 6 publications

References 40 publications

Separated Electron–Phonon and Phonon–Phonon Scatterings Across Interface in Thin Film LaCoO₃/SrTiO₃

Separated Electron–Phonon and Phonon–Phonon Scatterings Across Interface in Thin Film LaCoO₃/SrTiO₃

Integration of Multijunction Absorbers and Catalysts for Efficient Solar‐Driven Artificial Leaf Structures: A Physical and Materials Science Perspective

Ultrafast Dynamic Terahertz Response of Ti₂O₃ Film during Photoinduced Metal–Insulator Transition

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Photoinduced insulator-to-metal transition and coherent acoustic phonon propagation in LaCoO3 thin films explored by femtosecond pump-probe ellipsometry

Cited by 6 publications

References 40 publications

Separated Electron–Phonon and Phonon–Phonon Scatterings Across Interface in Thin Film LaCoO3/SrTiO3

Separated Electron–Phonon and Phonon–Phonon Scatterings Across Interface in Thin Film LaCoO3/SrTiO3

Integration of Multijunction Absorbers and Catalysts for Efficient Solar‐Driven Artificial Leaf Structures: A Physical and Materials Science Perspective

Ultrafast Dynamic Terahertz Response of Ti2O3 Film during Photoinduced Metal–Insulator Transition

Contact Info

Product

Resources

About

Separated Electron–Phonon and Phonon–Phonon Scatterings Across Interface in Thin Film LaCoO₃/SrTiO₃

Separated Electron–Phonon and Phonon–Phonon Scatterings Across Interface in Thin Film LaCoO₃/SrTiO₃

Ultrafast Dynamic Terahertz Response of Ti₂O₃ Film during Photoinduced Metal–Insulator Transition