First-principles electronic structure of rare-earth arsenides

The electronic properties of rare-earth arsenides have been calculated from first principles. In the calculations we have treated the rare-earth f ele ctrons both as core-like and as valence-like electrons. We consider the cha nges in the energy bands and in the density of states near the Fermi level which are found to be relevant, except for the case of LuAs, and discuss th is in relation with the role played from the rare-earth 5d derived states. Moreover we show that the rare-earth 5d related bands are particularly sens itive to the variation of the lattice constant; change in the lattice const ant of less than 1% leads to a different behaviour with respect to the cros sing of the rare-earth 5d derived bands and the As 4p derived bands along t he Delta -direction. This point is discussed in connection with the possibi lity of having a semimetal-semiconductor transition in the rare-earth arsen ides.