Hardening of the ferroelectric soft mode in SrTiO3 thin films

Katayama, Ikufumi; Shimosato, H.; Rana, D. S.; Kawayama, Iwao; Tonouchi, Masayoshi; Ashida, Masaaki

doi:10.1063/1.2991442

Cited by 38 publications

(32 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Perhaps not quite, but it does strongly suggest that the vast majority of experimentally observed incidences of permittivity suppression are not due to intrinsic interfacial effects, but rather due to shortcomings in sample quality. This is nicely illustrated by very recent work by Katayama et al [43], where the kind of soft-mode hardening previously seen in the classic study by Sirenko et al [33] were largely obviated by simple thermal annealing of the SrTiO 3 thin films.…”

Section: Feature Articlesupporting

confidence: 49%

Ferroelectrics at the nanoscale

Gregg¹

2009

Physica Status Solidi (a)

View full text Add to dashboard Cite

There are several factors which make the investigation and understanding of nanoscale ferroelectrics particularly timely and important. Firstly, there is a market pressure, primarily from the electronics industry, to integrate ferroelectrics into devices with progressive decreases in size and increases in morphological complexity. This is perhaps best illustrated through the roadmaps for product development in FeRAM (Ferroelectric Random Access Memory) where the need for increases in bit density will require a move from 2D planar capacitor structures to 3D trenched capacitors in the next few years. Secondly, there is opportunity for novel exploration, as it is only relatively recently that developments in thin film growth of complex oxides, self‐assembly techniques and high‐resolution ‘top–down’ patterning have converged to allow the fabrication of isolated and well‐defined ferroelectric nanoshapes, the properties of which are not known. Thirdly, there is an expectation that the behaviour of small scale ferroelectrics will be different from bulk, as this group of functional materials is highly sensitive to boundary/surface conditions, which are expected to dominate the overall response when sizes are reduced into the nanoscale regime.This feature article attempts to introduce some of the current areas of discovery and debate surrounding studies on ferroelectrics at the nanoscale. The focus is directed primarily at the search for novel size‐related properties and behaviour which are not necessarily observed in bulk. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

show abstract

Section: Feature Articlesupporting

confidence: 49%

Ferroelectrics at the nanoscale

Gregg¹

2009

Physica Status Solidi (a)

View full text Add to dashboard Cite

show abstract

“…In addition, γ TO1 values range from 2 to 6 THz; in the measured frequency range, these values are larger than the soft-mode frequencies, as shown in Fig. 5(c), while γ TO1 of the STO/MgO thin film was less than 3 THz at temperatures below 200 K [19,20]. It should be noted that γ TO1 begins to increase with a decrease in temperature at T c (~170 K).…”

Section: Resultsmentioning

confidence: 79%

Strain-Induced Ferroelectricity of a SrTiO3 Thin Film on a MgAl2O4 Substrate Observed by Terahertz Time-Domain Spectroscopy

Kinjo

Kawayama

Murakami

et al. 2011

J Infrared Milli Terahz Waves

Self Cite

View full text Add to dashboard Cite

A SrTiO 3 thin film was deposited on a MgAl 2 O 4 (100) substrate with a 3.5 % larger lattice constant than that of the SrTiO 3 . The temperature dependence of the dielectric dispersion of the SrTiO 3 thin film was measured by terahertz time-domain spectroscopy, and the dielectric strength and soft-mode frequency showed positive and negative peaks at around 170 K, respectively. In addition, a deviation of the dielectric constant from the theoretical fitting curve in the gigahertz range and an increase in the value of the damping factor were observed below the ferroelectric transition temperature. These phenomena strongly indicate the emergence of ferroelectricity at around 170 K.

show abstract

“…[146][147][148][149] Hardening of the soft mode was observed up to 6 cm −1 with an externally applied DC electric field of 150 V. The dielectric constant can be tuned up to 11% for 100 V. Given that the soft mode lies in the THz regime, the ultrafast electromagnetic pulse of resonance frequency can Adv. [146][147][148][149] Hardening of the soft mode was observed up to 6 cm −1 with an externally applied DC electric field of 150 V. The dielectric constant can be tuned up to 11% for 100 V. Given that the soft mode lies in the THz regime, the ultrafast electromagnetic pulse of resonance frequency can Adv.…”

Section: Soft Mode In Srtio 3 Driven To the Anharmonic Regime Using Imentioning

confidence: 99%

“…The ferroelectric soft mode in SrTiO 3 is sensitive to the external perturbations such as strain, applied electric field, and crystalline quality of the samples which has been extensively studied using THz-TDS. [146][147][148][149] Hardening of the soft mode was observed up to 6 cm −1 with an externally applied DC electric field of 150 V. The dielectric constant can be tuned up to 11% for 100 V. Given that the soft mode lies in the THz regime, the ultrafast electromagnetic pulse of resonance frequency can Adv. Optical Mater.…”

Section: Soft Mode In Srtio 3 Driven To the Anharmonic Regime Using Imentioning

confidence: 99%

Terahertz Electrodynamics in Transition Metal Oxides

Prajapati

Dagar

et al. 2019

Advanced Optical Materials

Self Cite

View full text Add to dashboard Cite

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adom.201900958. 2−y 2 , d z 2 ) levels. [35] The splitting of the d-orbital was successfully explained by the crystal field theory. The ground state properties of these materials are mainly governed by the two interactions; i) the electron correlations (U) and, ii) SOC (λ) in the crystal field split narrow bands. [36] Among d electron systems, electrons in 3d TMOs experiences large electron correlations due to localized nature of 3d orbitals. The idea of electron-electron interaction was given by Sir N. F. Mott in 1949. It originated from the fact that the NiO was expected to be a metal according to the band theory, while the experiments showed insulating behavior. [37][38][39][40][41] This disagreement of experiments with the theory was explained by Hubbard who attributed the insulating state to the splitting

show abstract

Hardening of the ferroelectric soft mode in SrTiO3 thin films

Cited by 38 publications

References 17 publications

Ferroelectrics at the nanoscale

Ferroelectrics at the nanoscale

Strain-Induced Ferroelectricity of a SrTiO3 Thin Film on a MgAl2O4 Substrate Observed by Terahertz Time-Domain Spectroscopy

Terahertz Electrodynamics in Transition Metal Oxides

Contact Info

Product

Resources

About