Electronic Structure of the Cubic Compounds ReGa3 (Re = Er, Tm, Yb, and Lu)

The electronic structure of ErGa3 and its isostructural compounds
with Tm, Yb, and Lu are investigated with a highly accurate band
structure scheme in LDA and GGA and warped muffin-tin
approximation. In contrast to other investigations, the 4f
electrons of the constituent Re are also treated as part of the
valence bands. The position of the corresponding 4f bands relative
to the Fermi energy E-F strongly depends on the nuclear charge of
Re. In Lu, they lie almost by 0.5 Ryd below E-F and are extremely
narrow. In Er, both in LDA and GGA, the 4f bands are found to be
very close to the Fermi level E-F. Assuming most of the 4f
electrons to be part of the core removes the disagreement almost
completely but produces a Fermi surface with a topology markedly
different from that proposed in previous investigations. The
intersections of the Fermi surface with planes are strongly varying
within the Brillouin zone, they do not well match with the sparse
experimental results. Investigations using the LDA + U scheme as
well as investigations of the dielectric response function are
sketched.