Pressure-induced electronic phase transition in compound EuCu2Ge2

16th International Conference on X-ray Absorption Fine Structure

Geondzhian, A.Y.^1 ; Yaroslavtsev, A.A.^1,2 ; Alekseev, P.A.^1,3 ; Chernikov, R.V.^4 ; Gaynanov, B.R.^1 ; Baudelet, F.^5 ; Nataf, L.^5 ; Menushenkov, A.P.^1

National Research Nuclear University, MEPhI (Moscow Engineering Physics Institute), Kashirskoe sh. 31, Moscow

115409, Russia^1

European XFEL GmbH, Albert-Einstein-Ring 19, Hamburg

22761, Germany^2

National Research Centre Kurchatov Institute, Kurchatov sq., Moscow

123182, Russia^3

DESY Photon Science, Notkestr., 85, Hamburg

D-22607, Germany^4

Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin

91190, France^5

关键词: Band structure calculation;    Electronic phase transition;    High pressure;    Integer values;    Pressure increase;    Pressure ranges;    SixGe1-x;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012112/pdf
DOI  :  10.1088/1742-6596/712/1/012112

来源: IOP

【 摘 要 】

We report the high-pressure XANES study of the electronic phase transition from 4f7to 4f6configuration of europium in the rare-earth compound EuCu2Ge2. The hydrostatic pressure dependence of the europium valence was obtained in a wide pressure range (1-30 GPa) at room temperature. It was found that upon the pressure increase above 20 GPa the europium valence does not reach the integer value +3 but stabilizes at 2.87. The experimental results were supported by the band structure calculations in the framework of DFT, which allowed us to discuss the features of 3d-4f hybridization in this system. The study also compares the mechanisms of external and "chemical" pressure by the Si substitution in Ge site in series EuCu2(SixGe1-x)2.