Vapour growth and crystal data of the thio(seleno)-hypodiphosphates Sn2P2S6, Sn2P2Se6, Pb2P2Se6 and their mixed crystals

Carpentier, C. D.; Nitsche, R.

doi:10.1016/0025-5408(74)90207-4

Cited by 125 publications

(35 citation statements)

References 11 publications

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“…Here we are to notice that the literature data on the physical properties of Pb 2 P 2 Se 6 are rather poor. It is known that this monoclinic crystal (the point symmetry group 2∕m [14]) is optically biaxial and transparent mainly in the infrared spectral range, with the fundamental absorption edge corresponding to the wavelength of 591 nm [14]. The temperature dependence of the heat capacity for Pb 2 P 2 Se 6 studied down to liquid-helium temperatures does not reveal structural phase transitions [15], thus confirming our assumption about the thermal stability of its properties.…”

Section: Introductionsupporting

confidence: 81%

“…The orientation of crystallographic axes was determined using an x-ray diffraction technique. The lattice parameters at room temperature and atmospheric pressure are a 6.606 Å, b 7.464 Å, c 11.3346 Å, and β 91.33 deg (see [14]), where the b axis is perpendicular to the symmetry mirror plane. Neglecting a small monoclinic angle, one can refer to the crystallographic coordinate system as orthogonal and label the coordinate axes as a 1, b 2, and c 3.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Acoustic and elastic anisotropy of acousto-optic Pb₂P₂Se₆ crystals

et al. 2014

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We have determined experimentally the acoustic wave velocities for Pb₂P₂Se₆ crystals and obtained complete matrices of the elastic stiffness and elastic compliance coefficients on this basis. The anisotropy of the acoustic wave velocities has been analyzed, and the spatial directions of propagation and polarization of the slowest acoustic waves have been determined. In the case of acousto-optic (AO) interaction with these waves, the AO figure of merit can reach extremely high values, thus making Pb₂P₂Se₆ a promising AO material for the infrared spectral range.

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Section: Introductionsupporting

confidence: 81%

Section: Experimental Methodsmentioning

confidence: 99%

Acoustic and elastic anisotropy of acousto-optic Pb₂P₂Se₆ crystals

et al. 2014

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“…The monoclinic elementary cell ( Fig. 1) contains two formula units and belong to P2 1 /c space group [28,29]. Structure of valence zone (Fig.…”

Section: Calculation Of Energetic Spectramentioning

confidence: 99%

Valence fluctuations in Sn(Pb)2P2S6 ferroelectrics

Yevych

Haborets

Medulych

et al. 2016

Low Temperature Physics

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The valence fluctuations which are related to the charge disproportionation of phosphorous ions P 4+ + P 4+ → P 3+ + P 5+ are the origin of ferroelectric and quantum paraelectric states in Sn(Pb)2P2S6 semiconductors. They involve recharging of SnPS3 or PbPS3 structural groups which could be represented as half-filled sites in the crystal lattice. Temperature-pressure phase diagram for Sn2P2S6 compound and temperature-composition phase diagram for (PbySn1−y)2P2S6 mixed crystals, which include tricritical points and where a temperature of phase transitions decrease to 0 K, together with the data about some softening of low energy optic phonons and rise of dielectric susceptibility at cooling in quantum paraelectric state of Pb2P2S6 are analyzed by GGA electron and phonon calculations and compared with electronic correlations models. The anharmonic quantum oscillators model is developed for description of phase diagrams and temperature dependence of dielectric susceptibility.

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“…Sn 2 P 2 S 6 single crystals were grown using a conventional vapour-transport method [8]. Single crystalline samples were oriented with X-ray diffraction method and prepared in the shape of parallelepipeds.…”

Section: Methodsmentioning

confidence: 99%