Electric field tuning of the Fano resonance in BaTiO<sub>3</sub>

Dwij, Vivek; De, Binoy Krishna; Sathe, Vasant

doi:10.1109/isaf51943.2021.9477359

Cited by 4 publications

(10 citation statements)

References 20 publications

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“…Considering the ground state

∣ (⟩, i)

, Raman tensor components will uphold the wavenumber‐dispersed asymmetry within the

∣ (⟩, ϒ)

space. The asymmetry parameter can be obtained from, 24,25

q goodbreak= \frac{(⟨⟩|, ϒ, \overset{truê}{T}, i)}{π E_{ϰ} (⟨⟩|, ϰ, \overset{truê}{T}, i)},

where

\overset{T}{true}

is the transition matrix. The

q

value also gives a measure of the correlation between the polar fluctuations and polar phonons.…”

Section: Resultsmentioning

confidence: 99%

“…The

q

value also gives a measure of the correlation between the polar fluctuations and polar phonons. A smaller

q

indicates a larger correlation, because

q

varies inversely with the configuration interaction of the system 24,25 . The quantity

(||, 1 / q)

estimates a measure of the electron–phonon coupling strength.…”

Section: Resultsmentioning

confidence: 99%

“…Fano asymmetry is also reported to be triggered by rapid polarization fluctuations in ferroelectric materials comprising nano‐polar domains 23 . Previously, Dwij et al studied Fano resonance in Pr‐doped SrTiO 3 having a relaxor ferroelectric nature 24,25 . The intrinsic polarization instability around the characteristic temperature, microscopic polar distortions, or short‐range structural distortions at yet higher temperatures and consequently a local tilt (considered as the order parameter for relaxor transition) within the TiO 6 octahedron leads to renormalization of polar phonon wavenumber.…”

Section: Introductionmentioning

confidence: 99%

“…47 Considering the ground state j ii, Raman tensor components will uphold the wavenumber-dispersed asymmetry within the j Υi space. The asymmetry parameter can be obtained from, 24,25 q ¼…”

Section: Introspecting the Effect Of Excitation Strength On Fano Inte...mentioning

confidence: 99%

“…23 Previously, Dwij et al studied Fano resonance in Pr-doped SrTiO 3 having a relaxor ferroelectric nature. 24,25 The intrinsic polarization instability around the characteristic temperature, microscopic polar distortions, or short-range structural distortions at yet higher temperatures and consequently a local tilt (considered as the order parameter for relaxor transition) within the TiO 6 octahedron leads to renormalization of polar phonon wavenumber. In fact, quasiparticle renormalization in the electronic band gap, excitonic effects regarding (non)linear optical absorption, thermal effects comprising electron-phonon coupling, role of phonons in relaxor ferroelectricity within related solid-state solutions, and so on served as some pivotal research interests regarding the low to high symmetry phases under varying thermodynamic conditions.…”

mentioning

confidence: 99%

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Laser‐induced Fano interference subsumed by electron–phonon coupling in orthorhombic KNbO₃ nano‐bricks: An ab initio vibrational and Raman spectroscopic investigation

Bhattacharjee

Chattopadhyay

2023

J Raman Spectroscopy

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Hydrothermally prepared potassium niobate (KNbO3) nanoparticles are characterized meticulously to explore various crystallographic, microstructural, morphological, optical, compositional, and lattice‐vibrational properties. Laser power‐dependent Raman spectroscopy is employed to study the Fano effect in asymmetrically broadened optic (LO/TO) phonon modes in the orthorhombic KNbO3 system, considering interference with the interband electronic continuum. The phonon softening, alterations in charge‐phonon coupling constant, linewidth and lifetime of phonon modes, and so on are explained in the light of theories formulated by Fano, Allen, and Hui, accompanying factor group analysis of the Raman‐active modes. Under local heating via focused laser irradiation, highly sensitive Raman spectra introspect perturbations in the generic vibrations at the first Brillouin zone center and moderations in the constructive/destructive interference conditions of resonant Fano scattering. Density functional theory (DFT)‐based calculations on phonon dispersion, density of phonon states, and relevant thermodynamic attributes decipher the theoretical background. Amid photoexcited electron plasma, the charge‐phonon coupling for distinct modes is strengthened considerably against strong excitation intensity without any unwanted anharmonicity, extensive lattice thermal expansion, phonon decay, or microscopic phase transformation. Finally, the direction of asymmetry, particle–particle, and particle–quasiparticle interactions are illustrated using Feynman diagrams for the associated A1 and B1 phonon modes.

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“…Considering the ground state

∣ (⟩, i)

, Raman tensor components will uphold the wavenumber‐dispersed asymmetry within the

∣ (⟩, ϒ)

space. The asymmetry parameter can be obtained from, 24,25

q goodbreak= \frac{(⟨⟩|, ϒ, \overset{truê}{T}, i)}{π E_{ϰ} (⟨⟩|, ϰ, \overset{truê}{T}, i)},

where

\overset{T}{true}

is the transition matrix. The

q

value also gives a measure of the correlation between the polar fluctuations and polar phonons.…”

Section: Resultsmentioning

confidence: 99%

“…The

q

value also gives a measure of the correlation between the polar fluctuations and polar phonons. A smaller

q

indicates a larger correlation, because

q

varies inversely with the configuration interaction of the system 24,25 . The quantity

(||, 1 / q)

estimates a measure of the electron–phonon coupling strength.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introspecting the Effect Of Excitation Strength On Fano Inte...mentioning

confidence: 99%

mentioning

confidence: 99%

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Laser‐induced Fano interference subsumed by electron–phonon coupling in orthorhombic KNbO₃ nano‐bricks: An ab initio vibrational and Raman spectroscopic investigation

Bhattacharjee

Chattopadhyay

2023

J Raman Spectroscopy

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Reversible optical control of Fano resonance and domain configuration at room temperature in BaTiO3

Dwij

Gupta³

et al. 2022

Journal of Applied Physics

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Despite the ubiquitous nature, control of the Fano resonance in insulators has remained unexplored. We have achieved reversible control of Fano resonance using optical control in BaTiO3 at room temperature. Raman spectroscopic signatures and first-principle calculations suggest that the Fano line shape arises from the coupling of the discrete phonons [A(TO1)] comprising oscillations of Ba against TiO6 octahedra and broad phonons A(TO2) arising from oscillations of Ti against O6. Modifications of the A(TO2) phonons by lattice strain under different light polarizations change the resonance condition, which alters the spectral line shape. Domain reconfiguration accompanied by lattice strain is verified using x-ray diffraction experiments carried out under laser light with different polarization.

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Laser-induced Fano asymmetry, electron-phonon coupling, and phase transition in lanthanide sesquioxide (Ln2O3; Ln = Eu, Gd, Dy) nanoparticles: A Raman spectroscopic investigation

Bhattacharjee

Chattopadhyay

2022

Journal of Applied Physics

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Laser power-dependent Raman spectroscopy is deployed to probe Fano interference in asymmetrically broadened [Formula: see text] modes and the associated line shift in three technologically sound, meticulously characterized rare-earth sesquioxide systems. Group theoretical analysis is accompanied to introspect the Raman-active optic modes in cubic, monoclinic, and trigonal phases and identify the laser heating-induced local phase transitions. With increasing laser intensity, a regular redshift and larger negative asymmetry in the Raman peaks are detected, which is attributed to moderations in Fano scattering by enhanced electron–phonon coupling amid the focussed photoexcited electron plasma and is illustrated using a Feynman diagram. A quantitative study is thereby performed to unveil the intrinsic nature of discrete-continuum Fano resonance in the nanoparticles of interest emphasizing the high sensitivity of Raman spectra to the excitation strength that perturbs the generic vibrational features at the Brillouin zone center by influencing the interference conditions, force constant, and length of the associated bonds compelled by tensile stress. A rising trend of the charge–phonon coupling constant [Formula: see text] with laser power validates a stronger particle–quasiparticle coupling, whereas a shorter anharmonic phonon lifetime [Formula: see text] indicates faster interactions. Using Allen's formalism, the charge density of states [Formula: see text] at the Fermi level per spin and molecule is calculated, which pertains to a negative regression dependence in the [Formula: see text] dynamics.

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Electric field tuning of the Fano resonance in BaTiO₃

Cited by 4 publications

References 20 publications

Laser‐induced Fano interference subsumed by electron–phonon coupling in orthorhombic KNbO₃ nano‐bricks: An ab initio vibrational and Raman spectroscopic investigation

Laser‐induced Fano interference subsumed by electron–phonon coupling in orthorhombic KNbO₃ nano‐bricks: An ab initio vibrational and Raman spectroscopic investigation

Reversible optical control of Fano resonance and domain configuration at room temperature in BaTiO3

Laser-induced Fano asymmetry, electron-phonon coupling, and phase transition in lanthanide sesquioxide (Ln2O3; Ln = Eu, Gd, Dy) nanoparticles: A Raman spectroscopic investigation

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Electric field tuning of the Fano resonance in BaTiO3

Cited by 4 publications

References 20 publications

Laser‐induced Fano interference subsumed by electron–phonon coupling in orthorhombic KNbO3 nano‐bricks: An ab initio vibrational and Raman spectroscopic investigation

Laser‐induced Fano interference subsumed by electron–phonon coupling in orthorhombic KNbO3 nano‐bricks: An ab initio vibrational and Raman spectroscopic investigation

Reversible optical control of Fano resonance and domain configuration at room temperature in BaTiO3

Laser-induced Fano asymmetry, electron-phonon coupling, and phase transition in lanthanide sesquioxide (Ln2O3; Ln = Eu, Gd, Dy) nanoparticles: A Raman spectroscopic investigation

Contact Info

Product

Resources

About

Electric field tuning of the Fano resonance in BaTiO₃

Laser‐induced Fano interference subsumed by electron–phonon coupling in orthorhombic KNbO₃ nano‐bricks: An ab initio vibrational and Raman spectroscopic investigation

Laser‐induced Fano interference subsumed by electron–phonon coupling in orthorhombic KNbO₃ nano‐bricks: An ab initio vibrational and Raman spectroscopic investigation