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摘要
The electronic structures of REH3 (RE = Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu) are extensively investigated using the parameter-free many-body perturbation GW calculations. The different symmetry hexagonal structures of REH3 almost present the same quasiparticle band structure both in the 4f-core and in the 4f-val cases. In the 4f-core case, the GGA + G(0)W(0) calculations overestimate the direct band gap of the hexagonal structure; but the same G(0)W(0) calculations in the cubic structure give a very suitable indirect band gap (around 1.9 eV). In the 4f-val case, for the hexagonal structure (GdH3), we find that the HSE03 calculations shift obviously the strongly localized 4f orbitals towards the high energy, and the shift is critical for the proper constructions and iterations of both G and W in the G(0)W/GW calculations of the electronic properties. In contrast to the cubic structure, the HSE03 calculations for the strong correlation of the localized 4f electrons in the hexagonal structure is not the critical factor for the acquirement of the appropriate band gap. The GGA + G(0)W(0) calculations (GdH3) improve greatly the DFT band gap (0.2 eV) of the antiferromagnetic hexagonal structure and present a band gap with 1.0 eV; while the GGA + G(0)W(0) calculations remove the small band overlap character (near Fermi level) of the ferromagnetic structure, and show a reasonable band gap with 1.5 eV at high symmetry G point. Therefore, to some extent, the GGA + G(0)W(0) calculations can appropriately deal with the exchange-correlation interaction and the excited state in the ferromagnetic or antiferromagnetic hexagonal structure of GdH3.
- 出版日期2018-2
- 单位贵州师范学院; 西华师范大学
