Origin of optical anomalies in the ferroelectric phase transition region of SbSI and SbSBr crystals

Audzijonis, A.; Kvedaravičius, S.; Paulikas, V.; Siroicas, J.; Mykolaitienė, N.; Šadžius, R.

doi:10.1080/00150199808229564

Cited by 9 publications

(5 citation statements)

References 3 publications

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“…2). The obtained shift of the Fermi level by E F ≈ 0.53 eV at the phase transition causes increase of the band gap in the ferroelectric phase nearly by the same value [10].…”

Section: Discussionmentioning

confidence: 91%

“…It results in the shifts the Fermi level and the entire XPS. In these crystals, optical band gap obtained from an isoabsorption curve (at the absorption coefficient value K = 1000 cm −1 ), is 1.86 eV at 300 K, while ferroelectric one is 1.93 eV at 273 K and increases at lower temperatures [10]. The Fermi level, obtained from the XPS, in electronic SbSI lies near the conduction band.…”

Section: Ab Initio Calculation Of the Energy Levelsmentioning

confidence: 98%

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Splitting of the XPS in Ferroelectric SbSI Crystals

2003

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The paper presents the X-ray photoelectron spectra (XPS) of the valence band and core levels of the ferroelectric SbSI single crystal. Results revealed the new phenomenon-splitting of the core levels at the phase transition temperature T cl . The XPS are measured with monochromatized Al K α radiation in the energy range 0-1400 eV and the temperature range 130-330 K. Experimentally obtained energies are compared with the results of theoretical ab initio calculations. This is the first observation of the splitting of the XPS in a ferroelectric crystal. The mechanism of the XPS splitting in SbSI crystals is discussed.

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“…2). The obtained shift of the Fermi level by E F ≈ 0.53 eV at the phase transition causes increase of the band gap in the ferroelectric phase nearly by the same value [10].…”

Section: Discussionmentioning

confidence: 91%

Section: Ab Initio Calculation Of the Energy Levelsmentioning

confidence: 98%

Splitting of the XPS in Ferroelectric SbSI Crystals

2003

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“…In this mechanism softening of a ferroelectric TO-phonon mode drives the crystal from a low symmetry C 9 2v (Pna2 1 ) ferroelectric phase to a high symmetry D 16 2h (Pnam) paraelectric phase at ∼288 K [10,30,31,33,35]. We note that several proposals for transitioning to an intermediate phase between 298 and 410 K have also been reported [34,39,40], where the proposed mechanisms [34,41,42] are consistent with models that also show displacive-type phase transition behavior in molecular dynamics simulations [43,44]. Figure 1(a) shows the crystal structure of SbSI in the ferroelectric phase [45] with several unit cells stacked vertically along the crystallographic c axis, which corresponds to the axis of spontaneous polarization [46].…”

Section: Resultsmentioning

confidence: 59%

Charge carrier coupling to the soft phonon mode in a ferroelectric semiconductor

Ziffer

Huber

Wang

et al. 2022

Phys. Rev. Materials

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Many crystalline solids possess strongly anharmonic "soft" phonon modes characterized by diminishing frequency as temperature approaches a critical point associated with a symmetry breaking phase transition. While electron-soft phonon coupling can introduce unique scattering channels for charge carriers in ferroelectrics, recent studies on the nonferroelectric lead halide perovskites have also suggested the central role of anharmonic phonons bearing resemblance to soft modes in charge carrier screening. Here we apply coherent phonon spectroscopy to directly study electron coupling to the soft transverse optical phonon mode in a ferroelectric semiconductor SbSI. Photogenerated charge carriers in SbSI are found to be exceptionally long lived and are associated with a transient electro-optical effect that can be explained by interactions between charge carriers and thermally stimulated soft phonon excitations. These results provide strong evidence for the role of electron-soft phonon coupling in the efficient screening of charge carriers and in reducing charge recombination rates, both desirable properties for optoelectronics.

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“…The ferroelectric semiconductors have an unusually large number of interesting properties [2][3][4][5][6][7][8]. Among them are the pyroelectric, piezoelectric, electromechanical, electro optical and other nonlinear optical effects.…”

Section: Introductionmentioning

confidence: 99%

The nature of anharmonicity and phase transition in SbSBr crystal

Audzijonis¹,

Žigas²,

Kvedaravičius³

et al. 2010

Phase Transitions

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The ferroelectric crystal structure of SbSBr is composed of [Sb(S, Br)] 1 chains parallel to the [001] axis. In paraelectric phase, the crystal structure is disordered. The theoretical investigation of dependence of potential energy V P (z) of Sb atoms on amplitudes of B 1u vibration symmetry coordinates along c(z)-axis have showed that each atom is shifted from the xy mirror plane by Dz up or down along [001]. The theoretical investigation of the average potential energy V P ðzÞ of all Sb atoms in unit cell revealed that in paraelectric phase in region of phase transition V P ðzÞ has double-well shape. This strong anharmonicity of V P ðzÞ is created by interaction between phonons.

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Origin of optical anomalies in the ferroelectric phase transition region of SbSI and SbSBr crystals

Cited by 9 publications

References 3 publications

Splitting of the XPS in Ferroelectric SbSI Crystals

Splitting of the XPS in Ferroelectric SbSI Crystals

Charge carrier coupling to the soft phonon mode in a ferroelectric semiconductor

The nature of anharmonicity and phase transition in SbSBr crystal

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