|Conţinutul numărului revistei|
| SM ISO690:2012|
SANS, J.; SANTAMARIA-PEREZ, David; POPESCU, Catalin; GOMIS, Oscar; MANJON, Francisco Javier; VILAPLANA, Rosario Isabel; MUNOZ, Alfonso Gonzalez; RODRIGUEZ-HERNANDEZ, Placida Rogelio; URSAKI, Veacheslav; TIGINYANU, Ion. Structural and vibrational properties of CdAl2S4 under high pressure: Experimental and theoretical approach. In: Journal of Physical Chemistry C. 2014, nr. 28(118), pp. 15363-15374. ISSN -.
|Journal of Physical Chemistry C|
|Numărul 28(118) / 2014 / ISSN - /ISSNe 1932-7447|
The behavior of defect chalcopyrite CdAl2S4 at high pressures and ambient temperature has been investigated in a joint experimental and theoretical study. High-pressure X-ray diffraction and Raman scattering measurements were complemented with theoretical ab initio calculations. The equation of state and pressure dependences of the structural parameters of CdAl2S4 were determined and compared to those of other AB2X4 ordered-vacancy compounds. The pressure dependence of the Raman-active mode frequencies is reported, as well as the theoretical phonon dispersion curves and phonon density of states at 1 atm. Our measurements suggest that defect chalcopyrite CdAl2S4 undergoes a phase transition above 15 GPa to a disordered-rocksalt structure, whose equation of state was also obtained up to 25 GPa. In a downstroke from 25 GPa to 1 atm, our measurements indicate that CdAl2S4 does not return to the defect chalcopyrite phase; it partially retains the disordered-rocksalt phase and partially transforms into the spinel structure. The nature of the spinel structure was confirmed by the good agreement of our experimental results with our theoretical calculations. All in all, our experimental and theoretical results provide evidence that the spinel and defect chalcopyrite phases of CdAl2S4 are competitive at 1 atm. This result opens the way to the synthesis of spinel-type CdAl2S4 at near-ambient conditions.
ab initio calculations,
High-pressure x-ray diffractions, Phonon density of state, Phonon dispersion curves, Raman Scattering measurements, Structural parameter, Theoretical calculations, Vibrational properties