XANES investigation of novel lanthanide-doped CuCr0.99Ln0.01S2 (Ln = La, Ce) solid solutions

Коротаев, Е. В.; Syrokvashin, Mikhail M.; Filatova, I. Yu.; Трубина, С. В.; Nikolenko, A. D.; Ivlyushkin, D. V.; Zavertkin, P. S.; Сотников, А. В.; Кривенцов, В. В.

doi:10.1007/s00339-020-03715-y

Cited by 11 publications

(35 citation statements)

References 25 publications

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“…The powder samples CuCrS 2 and CuCr 0.99 Ln 0.01 S 2 (Ln = La, Ce) were synthesized from the initial metal oxides (CuO, Cr 2 O 3 , La 2 O 3 , CeO 2 ) with purity of 99.99% using procedure described and reported previously in 11 . The current research was carried out using the samples from our previous work 11 . The synthesized samples were reported to be single-phase and isostructural to the initial CuCrS 2 -matrix 11 , 13 .…”

Section: Methodsmentioning

confidence: 99%

“…The current research was carried out using the samples from our previous work 11 . The synthesized samples were reported to be single-phase and isostructural to the initial CuCrS 2 -matrix 11 , 13 . The obtained crystal structure data agree well with the crystallographic data reported in 14 .…”

Section: Methodsmentioning

confidence: 99%

“…- metal atoms allows one to decrease the thermal conductivity due to the phonon scattering increase. It was reported, that cationic substitution of the CuCrS 2 layered dichalcogenide is an effective approach for improving the material physical properties 4 , 7 , 9 , 11 . In particular, the substitution of chromium with iron atoms at low-level doping concentration (x ≤ 0.03) results a significant increase of the Seebeck coefficient value in comparison with those for the initial CuCrS 2 -matrix 9 .…”

Section: Introductionmentioning

confidence: 99%

“…The heavy lanthanide atoms could be used to increase the phonon scattering due to the increase of the nanoscale inhomogeneity that, thereby, decrease the material thermal conductivity 1 , 2 . The doping of CuCrS 2 -matrix with lanthanide ions leads to the Seebeck coefficient value increase 11 . Thus, the combination of the above mentioned approaches could be considered as a promising way to optimize the thermoelectric efficiency of CuCrS 2 -based solid solutions.…”

Section: Introductionmentioning

confidence: 99%

“…( 1 ), one can conclude that the Seebeck coefficient of a p -type semiconductor is determined mainly by the valence band DOS as well as the Fermi level energy. The CuCrS 2 -based solid solutions are considered as p -type semiconductors 3 – 6 , 9 , 11 . Hence, the study of the electron density distribution in the valence band is of special interest.…”

Section: Introductionmentioning

confidence: 99%

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Valence band structure and charge distribution in the layered lanthanide-doped CuCr0.99Ln0.01S2 (Ln = La, Ce) solid solutions

Коротаев

Syrokvashin

Filatova

et al. 2021

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The comprehensive study of the electronic density distribution of CuCr0.99Ln0.01S2 (Ln = La, Ce) solid solutions was carried out using both X-ray photoelectron and emission spectroscopy. It was found that cationic substitution of chromium with lanthanum or cerium atoms does not significantly affect the atomic charges of the matrix elements (Cu, Cr, S) in the lanthanide-doped solid solutions. The copper atoms in the composition of CuCrS2-matrix and the lanthanide-doped solid solutions were found to be in the monovalent state. The chromium and lanthanide atoms were found to be in the trivalent state. This fact indicates the isovalent cationic substitution character. The sulfur atoms were found to be in the divalent state. The near-surface layers contain the additional oxidation forms of sulfur (S0, S4+, S6+) and copper (Cu2+) atoms. The detailed analysis of the valence band structure using DFT calculations has shown that partial DOS distribution character of the matrix elements is preserved after the cationic substitution. The experimental valence band spectra structure of CuCrS2-matrix and CuCr0.99Ln0.01S2 is determined by the occupied copper d-states contribution. The contribution of the lanthanide states in the valence band structure is lower in comparison with those for the matrix elements. The major contribution of the lanthanide states was found to be mainly localized near the conduction band bottom.

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