Electrons and phonons in the ternary alloy CaAl$_{2-x}$Si$_x$} as a function of composition

Matteo Giantomassi; Lilia Boeri; Giovanni B. Bachelet

doi:10.1103/PhysRevB.72.224512

paper

Electrons and phonons in the ternary alloy CaAl $_{2 - x}$ Si $_{x}$ } as a function of composition

arXiv:cond-mat/0509242 · doi:10.1103/PhysRevB.72.224512

Abstract

We report a detailed first-principles study of the structural, electronic and vibrational properties of the superconducting C $_{32}$ phase of the ternary alloy CaAl $_{2 - x}$ Si $_{x}$ , both in the experimental range $0.6 \leq x \leq 1.2$ , for which the alloy has been synthesised, and in the theoretical limits of high aluminium and high silicon concentration. Our results indicate that, in the experimental range, the dependence of the electronic bands on composition is well described by a rigid-band model, which breaks down outside this range. Such a breakdown, in the (theoretical) limit of high aluminium concentration, is connected to the appearance of vibrational instabilities, and results in important differences between CaAl $_{2}$ and MgB $_{2}$ . Unlike MgB $_{2}$ , the interlayer band and the out-of-plane phonons play a major role on the stability and superconductivity of CaAlSi and related C $_{32}$ intermetallic compounds.

Electrons and phonons in the ternary alloy CaAl $_{2 - x}$ Si $_{x}$ } as a function of composition

Abstract

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Electrons and phonons in the ternary alloy CaAl2−x​Six​} as a function of composition

Abstract

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Cited by in corpus (13)

Electrons and phonons in the ternary alloy CaAl $_{2 - x}$ Si $_{x}$ } as a function of composition