Observation of the First-Order Raman Scattering in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">SrTiO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Thin Films

Sirenko, A. A.; Акимов, И. А.; Fox, Jon R.; Clark, Anthony C.; Li, Hong Cheng; Si, Weidong; Xi, X. X.

doi:10.1103/physrevlett.82.4500

Cited by 171 publications

(133 citation statements)

References 21 publications

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“…3), there are two more relatively sharp modes at 174.9 and 788.1 cm À1 that are not assignable to second-order scattering. We ascribe the former to TO 2 and the later to LO 4 firstorder Raman scattering modes 13,14 originating from lowering of the crystal symmetry with the silicon impurity doped STO ceramics as a result of breaking of inversion symmetries and it is consistent with the findings from the XRD analysis. The "silent" TO 2 and LO 2 modes are both at 173 cm À1 in undoped STO, as first determined by the early electric-field induced Raman scattering studies 15,16 by Worlock and Fleury.…”

Section: Resultssupporting

confidence: 78%

Disorder driven structural and dielectric properties of silicon substituted strontium titanate

Dugu

Pavunny

Sharma

et al. 2015

Journal of Applied Physics

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A systematic study on structural, microstructural, optical, dielectric, and electrical properties of phase-pure silicon-modified SrTiO3 polycrystalline electroceramics synthesized using high energy solid state reaction techniques is presented. The asymmetry and splitting in the x-ray diffractometer spectra and the observation of first order transverse optical TO2 and longitudinal optical LO4 modes in Raman spectra (nominally forbidden) revealed the distortion in the cubic lattice as a result of breaking of inversion symmetry due to doping. A bandgap Eg of 3.27 eV was determined for the sample by diffuse reflectance spectroscopy. A high dielectric constant of ∼400 and very low dielectric loss of ∼0.03 were obtained at 100 kHz near ambient conditions. The temperature dependence of the dielectric data displayed features of high temperature relaxor ferroelectric behavior as evidence of existence of polar nano-regions. The ac conductivity as a function of frequency showed features typical of universal dynamic response and obeyed a power law σac=σdc+Aωn. The temperature dependent dc conductivity followed an Arrhenius relation with activation energy of 123 meV in the 200–500 K temperature range. The linear dielectric response of Pt/SrSi0.03Ti0.97O3/Pt dielectric capacitors was well characterized. The measured leakage current was exceptionally low, 13 nA/cm2 at 8.7 kV/cm, revealing an interface blocked bulk conduction mechanism.

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Section: Resultssupporting

confidence: 78%

Disorder driven structural and dielectric properties of silicon substituted strontium titanate

Dugu

Pavunny

Sharma

et al. 2015

Journal of Applied Physics

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“…The laser power density at the sample was second order Raman modes which arises due to creation or destruction of two phonons is consistent with previous reports 6, 47,48 . The polarized raman spectra has been taken (shown in Fig.…”

Section: Raman Spectroscopy Measurementssupporting

confidence: 78%

Anomalous ferroelectric switching dynamics in single crystalline SrTiO3

Shukla

Mukhopadhyay

2016

Journal of Applied Physics

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Pure SrTiO 3 in bulk form is known to be an 'incipient ferroelectric' where quantum fluctuations of lattice positions prevent long range ferroelectric ordering at finite temperature. We show evidence and identify the origin of ferroelectric relaxation up to nearly room temperature in single crystalline SrT iO 3 . Strikingly, the origin of the observed ferroelectric switching is intrinsic that is coherent switching of surface nanopolar regions and not due to the nucleation and growth of domains, as described by Kolmogorov-Avrami-Ishibashi (KAI) Model.

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“…This indicates a stronger contribution of the defect-induced mechanism in Raman scattering in the strontium-rich films. The breakdown of the symmetry selection rules has been previously observed in Raman scattering from SrTiO 3 films grown by PLD, 17 and attributed to polar nanoregions associated with oxygen vacancies 17 or dipole moments associated with polar grain boundaries in polycrystalline or textured samples. 18 The samples studied here are single-crystalline films having no grain boundaries, so this effect is not present.…”

mentioning

confidence: 94%

Ferroelectricity in nonstoichiometric SrTiO3 films studied by ultraviolet Raman spectroscopy

Ténné

Farrar

Brooks

et al. 2010

Applied Physics Letters

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Homoepitaxial Sr1+xTiO3+δ films with −0.2≤x≤0.25 grown by reactive molecular-beam epitaxy on SrTiO3 (001) substrates have been studied by ultraviolet Raman spectroscopy. Nonstoichiometry for strontium-deficient compositions leads to the appearance of strong first-order Raman scattering at low temperatures, which decreases with increasing temperature and disappears at about 350 K. This indicates the appearance of a spontaneous polarization with a paraelectric-to-ferroelectric transition temperature above room temperature. Strontium-rich samples also show a strong first-order Raman signal, but the peaks are significantly broader and exhibit a less pronounced temperature dependence, indicating a stronger contribution of the disorder-activated mechanism in Raman scattering.

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Observation of the First-Order Raman Scattering inSrTiO3Thin Films

Cited by 171 publications

References 21 publications

Disorder driven structural and dielectric properties of silicon substituted strontium titanate

Disorder driven structural and dielectric properties of silicon substituted strontium titanate

Anomalous ferroelectric switching dynamics in single crystalline SrTiO3

Ferroelectricity in nonstoichiometric SrTiO3 films studied by ultraviolet Raman spectroscopy

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