First-principles density-functional calculations within the local spin-density approximation and the generalized gradient approximation are reported for pyrochlore Cd2Os2O7 and Cd2Re2O7. The transition-metal t2g manifolds are found to be well separated in energy from the O 2p bands and from the higher-lying eg and Cd derived bands. The active electronic structure in the t2g manifold near the Fermi energy EF is found to be significantly modified by spin-orbit interactions, which we include. Both materials show semimetallic band structures, in which the EF lies in an pseudogap. The band structure of Cd2Os2O7 near EF is dominated by very heavy-hole and electron bands, though at EF the electron sections are lighter. Cd2Re2O7 has heavy-hole bands but moderate mass electron states. The results are discussed in terms of measured transport and thermodynamic properties of these compounds as well as the very different ground states of these two materials.
|Original language||English (US)|
|Number of pages||8|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Apr 15 2002|
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics