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S. Steiner, H. Michor, O. Sologub, V. Levytskyy, V. Babizhetskyy, B.Ya. Kotur:
"The Solid Solution Series LuCo_1-xNi_xC₂: Crystal Structure and Electronic Properties";
Poster: SCTE2018, The 21st International Conference on Solid Compounds of Transition Elements, Wien; 25.03.2018 - 29.03.2018.

A series of polycrystalline solid solutions LuCo_1-xNi_xC₂ (x = 0.0, 0.33, 0.5, 0.67, 1.0) were investigated by means of x-ray diffraction and specific heat measurements as well as ab-initio electronic structure studies. The crystal structures of all investigated samples refer to the CeNiC₂-type structure* (space group Amm2 and Pearson symbol oS8). The non-isoelectronic substitution of Co by Ni causes a small increase of the unit cell volume and a non-monotonous variation of the a and c lattice parameters, as earlier reported for HoCo_1-xNi_xC₂.§
In order to analyze the changes in the electronic structure of this solid solution series, we used the projector augmented plane-wave (PAW) method in combination with the virtual crystal approximation (VCA). All calculations were performed using the PBE GGA (Perdew Burke Ernzerhof generalized gradient approximation) functional. For LuCoC₂ the density of states at the Fermi energy is mainly dominated by the 3d-band of Co, whereas for LuNiC₂ the 3d-band is almost filled and the contributions come from Lu, Ni and C. The 3d-band filling is successfully depicted via the VCA scheme, we present the variation of the density of states and band structure for the whole solid solution. The densities of states at the Fermi level are compared to experimental data and Fermi surface features will be discussed.
* W. Jeitschko and M. Gerss. J. Less Common Met. 116, 147 (1986)
§ H. Michor, S. Steiner, A. Schumer, M. Hembara, V. Levytskyy, V. Babizhetskyy, B. Kotur. J. Magn. Magn. Mat. 441, 67 (2017)