Electronic and structural properties of superconducting MgB${}_2$, CaSi${}_2$ and related compounds

Abstract

We report a detailed study of the electronic and structural properties of the 39K superconductor \mgbtwo and of several related systems of the same family, namely \mgalbtwo, \bebtwo, \casitwo 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 $\sigma$-bonding bands contribute significantly at the Fermi level. Similarities and differences between \mgbtwo and \bebtwo (whose superconducting properties have not been yet investigated) are analyzed in detail. Our calculations for \mgalbtwo show that metal substitution cannot be fully described in a rigid band model. \casitwo 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.

Revised version, Phys.Rev.B in press

References in corpus (1)

• Boron Isotope Effect in Superconducting MgB${}_2$

Cited by in corpus (45)

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• High-pressure synthesis of pure and doped superconducting MgB2 compounds
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• Enhanced Critical parameters of nano-Carbon doped MgB2 Superconductor
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• Tuning topological disorder in MgB${}_2$
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• Anisotropic, Fermi-Surface-Induced Variation in T_c in MgB_2 Alloys
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• Theoretical evidences for enhanced superconducting transition temperature of CaSi${}_2$ in a high-pressure AlB${}_2$ phase