Weighted Density Approximation Description of YH3, LaH3 and CaB6
Abstract
Density functional calculations within the weighted density approximation (WDA) are presented for YH3 and LaH_3. We investigate some commonly used pair-distribution functions G. These calculations show that within a consistent density functional framework a substantial insulating gap can be obtained while at the same time retaining structural properties in accord with experimental data. Our WDA band structures agree with those of GW approximation very well. It shows that there is no strong correlation in H 1s states, and the absence of self-interaction in H 1s is crucial to obtain correct band structures of these rare earth trihydrites. But the calculated band gaps are still 1.0-2.0 eV smaller than experimental findings. We also calculated the band structure of CaB_6. The LDA predicts a tiny band gap of 0.12 eV, while the WDA predicts 0.8 eV, which agrees well with the experimental finding that CaB6 is a semiconductor with a band gap of 1.0 - 1.2 eV.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARL38005W