Electronic structure, magnetic properties, and mixed valence character of Ce2Ni3Si5 from first principles calculations

5 years ago

Electronic structure, magnetic properties, and mixed valence character of Ce2Ni3Si5 from first principles calculations

Ismail A. M. Ibrahim

Cerium intermetallic compounds exhibit anomalous physical properties such as heavy fermion and Kondo behaviors. Here, an ab initio study of the electronic structure, magnetic properties, and mixed valence character of Ce2Ni3Si5 using density functional theory (DFT) is presented. Two theoretical methods, including pure Perdew–Burke–Ernzerhof (PBE) and PBE + U, are used. In this study, Ce3+ and Ce4+ are considered as two different constituents in the unit cell. The formation energy calculations on the DFT level propose that Ce is in a stable mixed valence of 3.379 at 0 K. The calculated electronic structure shows that Ce2Ni3Si5 is a metallic compound with a contribution at the Fermi level from Ce 4f and Ni 3d states. With the inclusion of the effective Hubbard parameter (Ueff), the five valence electrons of 5 Ce3+ ions are distributed only on Ce3+ 4f orbitals. Therefore, the occupied Ce3+ 4f band is located in the valence band (VB) while Ce4+ 4f orbitals are empty and Located at the Fermi level. The calculated magnetic moment in Ce2Ni3Si5 is only due to cerium (Ce3+) in good agreement with the experimental results. The Ueff value of 5.4 eV provides a reasonable magnetic moment of 0.981 μB for the unpaired electron per Ce3+ ion. These results may serve as a guide for studying present mixed valence cerium-based compounds. © 2017 Wiley Periodicals, Inc. The mixed valence character of cerium in intermetallic compounds is responsible for their anomalous physical properties. Using the formation energy calculations on the DFT level, it is found that Ce is in a stable mixed valence of 3.379 at 0 K in Ce2Ni3Si5. The calculated magnetic moment is only due to Ce3+ in good agreement with the experimental results.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/jcc.24906