DFT calculations on the electronic structure of CuTe2 and Cu7Te4

The electronic structures of CuTe2 and Cu7Te4 were determined from first principles. The band structures, densities of states and projected contributions of atomic states were calculated with DFT ASWand FP-LAPW codes. Both compounds stabilize by establishing metallic instead of ionic systems. This behaviour is explained in terms of partly occupied valence bands that result from a range of Cu–Te, Cu–Cu and Te–Te bonding. As a consequence the Cu–d states show contributions to the valence states, while their maxima lie at −2 eV below the Fermi energy. In CuTe2 the bonding of Te–Te–π ∗ and Cu–d states leads to an overlap of valence and conduction bands. Thus the character of the valence band is of Cu–eg and Te–p character.  2003 Elsevier SAS. All rights reserved.