Pressure-Induced Phase Transitions in Cadmium Thiogallate CdGa2Se4

Grzechnik, Andrzej; Ursaki, V. V.; Syassen, K.; Loa, I.; Tiginyanu, I. M.; Hanfland, Michael

doi:10.1006/jssc.2001.9224

Cited by 49 publications

(101 citation statements)

References 21 publications

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“…Figure 6 shows the experimental and theoretical pressure dependence of the unit-cell volume and c/a ratio in DC-CdGa 2 Se 4 . It is clear that the decrease of the experimental volume with increasing pressure 15 is considerably smaller than the one expected from our theoretical calculations, which do not include any kind of disorder. On the other hand, there is an increase of the experimental c/a ratio with increasing pressure 15 which is much smaller than the increase of the c/a ratio theoretically predicted.…”

Section: First Upstrokecontrasting

confidence: 78%

“…Since no new Raman modes have been observed at high pressures in DC-CdGa 2 Se 4 , these two DS structures can be discarded to occur at high pressures in our compound. Therefore, we can conclude that our Raman measurements can be interpreted on the basis of a partial transformation from the DC to the DS structure (models 2 or 3 in Table II) above 6-8 GPa in agreement with Ursaki et al 11 It is noteworthy that despite the fact that Raman measurements support the existence of cation disorder resulting in a partial transformation from the DC to the DS phase, XRD measurements up to 21 GPa do not show evidence of a change in diffraction peaks supporting this phase transition; 15 however, this is not surprising because on one hand, the transition is not completed, and XRD measurements have difficulty in detecting minor phases in a mixture of phases, and on the other hand, both structures have the same systematic absences in the indexed lattice planes so they are very difficult to distinguish, even as pure phases. However, a deeper analysis of XRD data can be done if we compare experimental and theoretical data.…”

Section: First Upstrokesupporting

confidence: 77%

“…13,14 Recent x-ray diffraction (XRD) measurements up to 30 GPa in CdGa 2 Se 4 confirmed a phase transition from the DC structure to the DR phase above 21 GPa. 15 This phase transition was found to be non-reversible, and on decreasing pressure, CdGa 2 Se 4 was found to transform to a different metastable phase. The authors proposed that the observed XRD peaks of the new metastable phase could be explained by a cubic DZ structure, where one out of four cation sites is randomly occupied by a vacancy.…”

Section: Introductionmentioning

confidence: 95%

“…We have assigned the high-pressure phase of CdGa 2 Se 4 to the Raman-inactive DR phase, in good agreement with XRD measurements. 15 The evolution of the Raman peak frequencies (symbols) as a function of pressure for DC-CdGa 2 Se 4 is shown in Fig. 3 and compared to our ab initio calculated frequencies (lines).…”

Section: First Upstrokementioning

confidence: 99%

“…CdGa 2 Se 4 is one of the most studied adamantine ternary compounds, and the behavior of DC-CdGa 2 Se 4 under pressure has been subject of recent studies. [11][12][13][14][15][16] In particular, two Raman scattering measurements under pressure 11,12 found a phase transition near 20 GPa to the disordered rock salt (DR) structure [see Fig. 1(c)].…”

Section: Introductionmentioning

confidence: 99%

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High-pressure optical and vibrational properties of CdGa2Se4: Order-disorder processes in adamantine compounds

Gomis

Vilaplana

Manjón

et al. 2012

Journal of Applied Physics

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High pressure structural stability of BaLiF3 J. Appl. Phys. 110, 123505 (2011) Pressure effects on the transitions between disordered phases in supercooled liquid silicon J. Chem. Phys. 135, 204508 (2011) Microfabrication of controlled-geometry samples for the laser-heated diamond-anvil cell using focused ion beam technology Rev. Sci. Instrum. 82, 115106 (2011) First-principles investigations of elastic stability and electronic structure of cubic platinum carbide under pressure J. Appl. Phys. 110, 103507 (2011) Additional information on J. Appl. Phys. High-pressure optical absorption and Raman scattering measurements have been performed in defect chalcopyrite (DC) CdGa 2 Se 4 up to 22 GPa during two pressure cycles to investigate the pressure-induced order-disorder phase transitions taking place in this ordered-vacancy compound. Our measurements reveal that on decreasing pressure from 22 GPa, the sample does not revert to the initial phase but likely to a disordered zinc blende (DZ) structure the direct bandgap and Raman-active modes of which have been measured during a second upstroke. Our measurements have been complemented with electronic structure and lattice dynamical ab initio calculations. Lattice dynamical calculations have helped us to discuss and assign the symmetries of the Raman modes of the DC phase. Additionally, our electronic band structure calculations have helped us in discussing the order-disorder effects taking place above 6-8 GPa during the first upstroke.

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Section: First Upstrokecontrasting

confidence: 78%

Section: First Upstrokesupporting

confidence: 77%

Section: Introductionmentioning

confidence: 95%

Section: First Upstrokementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-pressure optical and vibrational properties of CdGa2Se4: Order-disorder processes in adamantine compounds

Gomis

Vilaplana

Manjón

et al. 2012

Journal of Applied Physics

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Temperature dependence of the structural and optical properties of the amorphous-to-crystalline transition in CdGa2Se4 thin films

El‐Sayad

Sakr

2004

phys. stat. sol. (a)

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Nearly stoichiometric thin films of CdGa2Se4 were deposited, by conventional thermal evaporation of presynthesized ingot material, onto quartz and Corning glass substrates. The chemical composition of the samples was determined by means of energy‐dispersive X‐ray spectrometry. X‐ray diffraction studies revealed that the as‐deposited and annealed films at Ta = 473 and 573 K have an amorphous phase, while those annealed at Ta ≥ 673 K are crystalline with a single phase of a defective chalcopyrite structure similar to that of the synthesized material. The unit cell lattice parameters of both the synthesized material and the crystalline films were determined and compared with reported data. The optical constants (n, k) and the film thickness (t) of the films were determined from optical transmittance data using the Swanepoel method. The dispersion parameters were determined from an analysis of the refractive index. An analysis of the optical absorption spectra revealed a non‐direct energy gap characterizing the amorphous films, while a direct energy gap characterized the crystalline films. The annealing temperature dependence of the corresponding energy gaps was found to fit a polynomial equation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Pressure‐induced structural phase transitions in materials and earth sciences

Manjón

Errandonea

2008

Physica Status Solidi (b)

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Pressure is an important thermodynamic parameter since it allows an increase of matter density by reducing volume. The reduction of volume by applying high pressures leads to an overall decrease of interatomic and intermolecular distances that allows exploring in detail atomic and molecular interactions. Therefore, high‐pressure research has improved our fundamental understanding of these interactions in solids, liquids and gasses. The study of the structure of matter under compression is a rapid developing field that is receiving increasing attention especially due to continuous experimental and theoretical developments. In this article, we give a brief description of the experimental and theoretical methods employed in the study of solid matter at high pressures and summarize the high‐pressure phases of the most relevant elements and inorganic compounds of the AX, A2X, AX2, ABX2, A2X3, ABX3, ABX4 and AB2X4 families giving an overview of the state of the art in high‐pressure research by highlighting recent discoveries, hot spots, controversial questions, and future directions of research. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Pressure-Induced Phase Transitions in Cadmium Thiogallate CdGa2Se4

Cited by 49 publications

References 21 publications

High-pressure optical and vibrational properties of CdGa2Se4: Order-disorder processes in adamantine compounds

High-pressure optical and vibrational properties of CdGa2Se4: Order-disorder processes in adamantine compounds

Temperature dependence of the structural and optical properties of the amorphous-to-crystalline transition in CdGa2Se4 thin films

Pressure‐induced structural phase transitions in materials and earth sciences

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