Superconductivity at 9 K in Mo5PB2 with evidence for multiple gaps

Michael A. McGuire; David S. Parker

doi:10.1103/PhysRevB.93.064507

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Superconductivity at 9 K in Mo5PB2 with evidence for multiple gaps

Michael A. McGuire, David S. Parker

DOI 10.1103/PhysRevB.93.064507 · Physical Review B

T1

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Abstract

Superconductivity is observed with critical temperatures near 9 K in the tetragonal compound Mo5PB2. This material adopts the Cr5B3 structure type common to superconducting Nb5Si3−xBx,Mo5SiB2, and W5SiB2, which have critical temperatures of 5.8–7.8 K. We have synthesized polycrystalline samples of the compound, made measurements of electrical resistivity, magnetic susceptibility, and heat capacity, and performed first-principles electronic structure calculations. The highest Tc value (9.2 K) occurs in slightly phosphorus rich samples, with composition near Mo5P1.1B1.9, and the upper critical field Hc2 at T=0 is estimated to be ≈17 kOe. Together, the measurements and band-structure calculations indicate intermediate coupling (λ=1.0), phonon mediated superconductivity. The temperature dependence of the heat capacity and upper critical field Hc2 below Tc suggest multiple superconducting gaps may be present.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Mo5PB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	9	Pressure not reported	unknown
Mo5P0.9B2.1 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8.7	Pressure not reported	zero_resistance
Mo5P0.9B2.1 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8.9	Pressure not reported	onset
Mo5PB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8.8	Pressure not reported	zero_resistance
Mo5PB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8.7	Pressure not reported	onset
Mo5P1.1B1.9 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	9.2	Pressure not reported	zero_resistance
Mo5P1.1B1.9 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	9.2	Pressure not reported	onset
Nb5SiB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7.2	Pressure not reported	unknown
Mo5SiB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5.8	Pressure not reported	unknown
W5SiB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5.8	Pressure not reported	unknown
W5-xTaxSiB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6.5	Pressure not reported	unknown
Nb5Si2.4B0.6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7.8	Pressure not reported	unknown
Mo3P Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5.5	Pressure not reported	unknown