Work

Evolution of the optical properties of chromium spinels CdCr 2 O 4 , HgCr 2 S 4 , and ZnCr 2 Se 4 under high pressure

Year: 2014

Type: article

Abstract: We report pressure-dependent reflection and transmission measurements on ZnCr${}_{2}$Se${}_{4}$, HgCr${}_{2}$S${}_{4}$, and CdCr${}_{2}$O${}_{4}$ single crystals at room temperature over a broad spectral range 200--24 000 cm${}^{\ensuremath{-}1}$. The pressure dependence of the phonon modes and the high-frequency electronic excitations indicate that all three compounds undergo a pressure-induced structural phase transition with critical pressures of 15, 12, and 10 GPa for CdCr${}_{2}$O${}_{4}$, HgCr${}_{2}$S${}_{4}$, and ZnCr${}_{2}$Se${}_{4}$, respectively. The eigenfrequencies of the electronic transitions are very close to the expected values for chromium crystal-field transitions. In the case of the chalcogenides, pressure induces a redshift of the electronic excitations, which indicates a strong hybridization of the Cr $d$ bands with the chalcogenide bands.

Source: Physical Review B

DOI: 10.1103/physrevb.89.125107

Authors: K. Rabia, L. Baldassarre, J. Deisenhofer, V. Tsurkan, C. A. Kuntscher

Institutions: University of Augsburg, Academy of Sciences of Moldova, Institute of Applied Physics

Language: Latvian

Topic: High-pressure geophysics and materials

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: bronze

Funders: Deutsche Forschungsgemeinschaft, Bayerische Forschungsstiftung

Awards: G1061299197, G580818053