Elastic isotropy, magnetic and electronic properties, bonding and non-covalent interactions analyses of HoFe4P12 filled-skutterudite: DFT + U + SOC, QTAIM and NCI investigations

Abstract

Several magnetic, electronic and elastic behaviors of HoFe4P12 filled-skutterudite remain unknown, therefore, this study is complementary to the experimental works carried out on this compound. Experimental results have shown that HoFe4P12 shows a ferromagnetic transition at around 5 K, therefore, the ground state properties studied in this work have been performed in this magnetic phase. The found value of the lattice constant is very close to that found experimentally. The elastic constants estimated in this work have shown that the studied compound is mechanically stable in the ground state. The study of elastic isotropy by the universal elastic anisotropy index, Zener anisotropy factor as well as the analysis of the directional dependence surface of Young’s modulus have shown that HoFe4P12 is elastically isotropic. The magnetic and electronic properties have been studied taking into account the strong correlation between 4f||3d electrons of Ho||Fe atoms and their spin–orbit effect (GGA + U + SOC). The electronic results have revealed a metallic behavior of HoFe4P12. The magnetic results have shown that Ho-atoms and Fe-atoms have magnetic moments of different signs, which exhibits the presence of a ferrimagnetic behavior close to that of ferromagnetic because of the very small magnetic moment value of Fe compared to that of Ho. Bonding analysis has indicated a metallicity of 10.15% with a predominant covalent character. NCI analysis has indicated the absence of weak attractive van-der-Waals interactions with a very strong contribution of repulsive interactions (steric effects) between Ho and Fe atoms.