The electronic structures of bulk trigonal, tetragonal, and hcp cobalt are calculated from first principles using density-functional theory. The results are used to predict lattice spacings, magnetic moments, and elastic properties. Attention is focused on the bcc and fcc structures, which are special cases of both the trigonal and tetragonal structures. An energy minimum is found around the fcc structure with properties in agreement with previous calculations and experiments. The bcc structure does not correspond to an energy minimum, and is therefore not a stable structure, with respect to tetragonal distortions. Our extensive calculations confirm the results of previous, more limited, density-functional calculations and are in contrast with experimental results that found metastable bcc cobalt thin films.
- Received 5 October 1998
- Published in the issue dated 15 August 1999
© 1999 The American Physical Society