Point-contact spectroscopy of Al- and C-doped MgB2: Superconducting energy gaps and scattering studies

P. Szabó; P. Samuely; Z. Pribulová; M. Angst; S. Bud’ko; P. C. Canfield; J. Marcus

doi:10.1103/PhysRevB.75.144507

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Point-contact spectroscopy of Al- and C-doped MgB2: Superconducting energy gaps and scattering studies

P. Szabó, P. Samuely, Z. Pribulová, M. Angst, S. Bud’ko, P. C. Canfield, J. Marcus

DOI 10.1103/PhysRevB.75.144507 · Physical Review B

T1

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Abstract

The two-band and/or two-gap superconductivity in aluminum- and carbon-doped MgB2 has been addressed by the point-contact spectroscopy. Two gaps are preserved in all samples with Tc′s down to 22K. The evolution of two gaps as a function of the critical temperature in the doped systems suggests the dominance of the band-filling effects, but for the increased Al doping, the enhanced interband scattering must also be considered. The extraction of the zero-energy density of states for the π and σ bands using a simple physical model demonstrates that significant changes in the relative weighting of the intraband scattering are created in the case of the C doping with the scattering in the π band enhanced faster than in the σ one. The Al doping does not change the relative weight of the scatterings within the bands.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Mg0.9Al0.1B2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	30.5	Pressure not reported	unknown
Mg0.8Al0.2B2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	23.5	Pressure not reported	unknown
Mg(B0.945C0.055)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	33	Pressure not reported	unknown
Mg(B0.935C0.065)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	28	Pressure not reported	unknown
Mg(B0.9C0.1)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	22	Pressure not reported	unknown
Mg(B0.979C0.021)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	37.5	Pressure not reported	unknown
Mg(B0.962C0.038)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	36.2	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