Identical superconducting gap on different Fermi surfaces of Ca(Al0.5Si0.5)2 with the AlB2 structure

S. Tsuda; T. Yokoya; S. Shin; M. Imai; I. Hase

doi:10.1103/PhysRevB.69.100506

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Identical superconducting gap on different Fermi surfaces of Ca(Al0.5Si0.5)2 with the AlB2 structure

S. Tsuda, T. Yokoya, S. Shin, M. Imai, I. Hase

DOI 10.1103/PhysRevB.69.100506 · Physical Review B

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Abstract

Angle-resolved photoemission spectroscopy of Ca(Al0.5Si0.5)2 (CaAlSi), which is a superconductor (transition temperature is 7.7 K) with the AlB2 structure, revealed that superconducting gaps on two Fermi surfaces (FSs) with three-dimensional character around Γ(A) and M(L) in the Brillouin zone provide essentially the same superconducting gap value (∼1.2meV±0.2meV). This is in contrast to the case of MgB2, in which different FSs exhibit different gap values. The reduced gap value 2Δ(0)/kBTc of ∼4.2±0.2 classifies CaAlSi as a moderately strong-coupling superconductor.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Ca(Al0.5Si0.5)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7.7	Pressure not reported	unknown
MgB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown