Extreme High-Field Superconductivity in Thin Re Films

F. N. Womack; D. P. Young; D. A. Browne; G. Catelani; J. Jiang; E. I. Meletis; P. W. Adams

doi:10.1103/PhysRevB.103.024504

paper

Extreme High-Field Superconductivity in Thin Re Films

arXiv:2010.07674 · doi:10.1103/PhysRevB.103.024504

Abstract

We report the high-field superconducting properties of thin, disordered Re films via magneto-transport and tunneling density of states measurements. Films with thicknesses in the range of 9 nm to 3 nm had normal state sheet resistances of $\sim$ 0.2 k $Ω$ to $\sim$ 1 k $Ω$ and corresponding transition temperatures in the range of 6 K to 3 K. Tunneling spectra were consistent with those of a moderate coupling BCS superconductor. Notwithstanding these unremarkable superconducting properties, the films exhibited an extraordinarily high upper critical field. We estimate their zero-temperature $H_{c 2}$ to be more than twice the Pauli limit. Indeed, in 6 nm samples the estimated reduced critical field $H_{c 2} / T_{c} \sim$ 5.6 T/K is among the highest reported for any elemental superconductor. Although the sheet resistances of the films were well below the quantum resistance $R_{Q} = h /4 e^{2}$ , their $H_{c 2}$ 's approached the theoretical upper limit of a strongly disordered superconductor for which $k_{F} ℓ \sim 1$ .

arXiv comment12 pages, 10 figures

Extreme High-Field Superconductivity in Thin Re Films

Abstract

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