Superconductivity in layered binary silicides: A density functional theory study

José A. Flores-Livas; Régis Debord; Silvana Botti; Alfonso San Miguel; Stéphane Pailhès; Miguel A. L. Marques

doi:10.1103/PhysRevB.84.184503

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Superconductivity in layered binary silicides: A density functional theory study

José A. Flores-Livas, Régis Debord, Silvana Botti, Alfonso San Miguel, Stéphane Pailhès, Miguel A. L. Marques

DOI 10.1103/PhysRevB.84.184503 · Physical Review B

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Abstract

A class of metal disilicides (of the form XSi2, where X is a divalent metal) crystallizes in the EuGe2 structure, formed by hexagonal corrugated silicon planes intercalated with metal atoms. These compounds are superconducting like other layered superconductors, such as MgB2. Moreover, their properties can be easily tuned either by external pressure or by negative chemical pressure (i.e., by changing the metal), which makes disilicides an ideal testbed to study superconductivity in layered systems. In view of this, we present an extensive density functional theory study of the electronic and phonon band structures as well as the electron-phonon interaction of metal disilicides. Our results explain the variation of the superconducting transition temperature with pressure and the species of the intercalating atom, and allow us to predict superconductivity for compounds not yet synthesized belonging to this family.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MgSi2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6	Pressure unresolved	unknown
CaSi2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1	Pressure unresolved	unknown
CaSi2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8	16 GPa	unknown
SrSi2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	2.2	Pressure unresolved	unknown
BaSi2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6.8	Pressure unresolved	unknown
RaSi2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8.3	Pressure unresolved	unknown
CaSi2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	14	16 GPa	unknown
BaSi2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8.9	Pressure not reported	unknown
MgB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	39	Pressure not reported	unknown