Structural, elastic, electronic and thermodynamic properties of uranium filled skutterudites UFe sub(4)P sub(12): First principle method

• Published in: Materials science in semiconductor processing 2014-11, Vol.27, p.368-379
• Main Authors: Ameri, Mohammed, Amel, Slamani, Abidri, Boualem, Ameri, Ibrahim, Al-Douri, Y, Bouhafs, Bachir, Varshney, Dinesh, Aze-Eddine, Adjadj, Nadia, Louahala
• Format: Article
• Language: English
• Subjects: Band structure of solids; Bulk modulus; Debye temperature; Elastic constants; Fermi level; Mathematical models; Semiconductors; Thermal expansion
• ISSN: 1369-8001
• DOI: 10.1016/j.mssp.2014.06.054

We present a theoretical study of structural, elastic, thermodynamic, and electronic properties of the uranium filled skutterudite UFe sub(4)P sub(12). We use the full-potential linear muffin-tin orbital (FP-LMTO) method in which the local density approximation (LDA) is used for the exchange-correlation (XC) potential. The lattice parameter at equilibrium, the bulk modulus, its pressure derivative, the elastic constants and the band structure energy of the filled skutterudite UFe sub(4)P sub(12) are calculated and systematically compared to available theoretical and experimental data. Herein, we use the total energy variation as function of strain technique to determine independent elastic constants and their pressure dependence. Furthermore, using quasi-harmonic Debye model with phonon effects, the effect of pressure P and temperature T on the lattice parameter, bulk modulus, thermal expansion coefficient, Debye temperature and the heat capacity of UFe sub(4)P sub(12) are investigated for the first time. Band structure of UFe sub(4)P sub(12) indicates a tendency of forming a pseudo-gap that appears above the Fermi level at Gamma point. This is a unique characteristic of skutterudite, especially when a single phosphorous p-band crosses the Fermi level. The crossing band is, indeed, pushed down by the repulsion of U f-resonance states.