Abstract
We report a detailed study of the electronic and structural properties of the 39 K superconductor and of several related systems of the same family, namely, and CaBeSi. Our calculations, which include zone-center phonon frequencies and transport properties, are performed within the local density approximation to the density functional theory, using the full-potential linearized augmented plane wave (FLAPW) and the norm-conserving pseudopotential methods. Our results indicate essentially three-dimensional properties for these compounds; however, strongly two-dimensional -bonding bands contribute significantly at the Fermi level. Similarities and differences between and (whose superconducting properties have not been yet investigated) are analyzed in detail. Our calculations for show that metal substitution cannot be fully described in a rigid band model. is studied as a function of pressure, and Be substitution in the Si planes leads to a stable compound similar in many aspects to diborides.
- Received 20 February 2001
DOI:https://doi.org/10.1103/PhysRevB.64.104507
©2001 American Physical Society