Superconductivity in noncentrosymmetric SrAuSi3

Masaaki Isobe; Masao Arai; Naoki Shirakawa

doi:10.1103/PhysRevB.93.054519

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Superconductivity in noncentrosymmetric SrAuSi3

Masaaki Isobe, Masao Arai, Naoki Shirakawa

DOI 10.1103/PhysRevB.93.054519 · Physical Review B

T1

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Abstract

Superconductivity in the noncentrosymmetric compound SrAuSi3 [BaNiSn3 type, I4mm,a=4.4024(9)Å, and c=9.942(2)Å] was studied by electrical resistivity, magnetic susceptibility, and specific heat measurements using single-phase polycrystalline samples, and ab initio band calculation. These measurements of the physical properties confirmed that the SrAuSi3 phase shows bulk superconductivity with a critical temperature of TC∼1.6K and an upper critical field of HC2∼1.8kOe. In the superconducting state, the electronic specific heat exhibits a thermal-activation-type temperature dependence and the Sommerfeld constant γ linearly responds to magnetic fields for low-energy excitation. These results clearly indicate that SrAuSi3 is a full-gap s-wave superconductor without a gap node in the superconducting order parameter. The density functional theory ab initio band calculation revealed that the electron system is composed of three kinds of Fermi surface: a cylindrical shape, a dumbbell shape, and a peculiar-shaped hole pocket. Fermi-surface splitting due to spin-orbit coupling exists only along limited directions in the Brillouin zone. Overall, the splitting energy size is small, insufficient to realize unconventional anisotropic superconductivity attributed to space-inversion symmetry breaking.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
SrAuSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.6	Pressure unresolved	zero_resistance
SrAuSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.9	Pressure unresolved	onset
SrAuSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.6	Pressure unresolved	midpoint
SrAuSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.8	Pressure unresolved	onset
SrAuSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.6	Pressure unresolved	unknown
CeRhSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.1	2.6 GPa	unknown
CeIrSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.6	2.63 GPa	unknown
CeCoGe3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	0.7	5.5 GPa	unknown
BaPtSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	2.25	Pressure not reported	unknown
CaIrSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	3.6	Pressure not reported	unknown
CaPtSi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	2.3	Pressure not reported	unknown