Mixed Valence of Ce and Its Consequences on the Magnetic State of Ce9Ru4Ga5: Electronic Structure Studies

Andrzej Ślebarski; Józef Deniszczyk; Dariusz Kaczorowski

doi:10.3390/ma13102377

Mixed Valence of Ce and Its Consequences on the Magnetic State of Ce₉Ru₄Ga₅: Electronic Structure Studies

Materials (Basel). 2020 May 21;13(10):2377. doi: 10.3390/ma13102377.

Authors

Andrzej Ślebarski¹, Józef Deniszczyk², Dariusz Kaczorowski^{3

4}

Affiliations

¹ Institute of Physics, University of Silesia in Katowice, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland.
² Institute of Materials Engineering, University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland.
³ Institute of Molecular Physics, Polish Academy of Sciences, Mariana Smoluchowskiego 17, 60-179 Poznań, Poland.
⁴ Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50-950 Wrocław, Poland.

Abstract

We report on X-ray photoelectron spectroscopy (XPS) and ab initio electronic structure investigations of a novel intermetallic material Ce 9 Ru 4 Ga 5 . The compound crystallizes with a tetragonal unit cell (space group I4 m m ) that contains three inequivalent Ce atoms sites. The Ce 3 d core level XPS spectra indicated an intermediate valence (IV) of selected Ce ions, in line with the previously reported thermodynamic and spectroscopic data. The ab initio calculations revealed that Ce1 ions located at 2 a Wyckoff positions possess stable trivalent configuration, whereas Ce2 ions that occupy 8 d site are intermediate valent. Moreover, for Ce3 ions, located at different 8 d position, a fractional valence was found. The results are discussed in terms of on-site and intersite hybridization effects.

Keywords: X-ray photoelectron spectroscopy; density functional theory; electronic band structure; hybridization; intermetallic Ce compounds; valence instability.