论文标题
薄胶片中极端的高场超导性
Extreme High-Field Superconductivity in Thin Re Films
论文作者
论文摘要
我们报告了通过磁通磁铁和状态测量的隧道密度的薄薄膜薄膜的高野外超导性能。厚度在9 nm至3 nm范围内的薄膜具有$ \ sim $ 0.2 k $ω$至$ \ sim $ \ sim $ 1 k $ω$的正常状态电阻，并且在6 k至3 k的范围内相应的过渡温度。隧道光谱与适度的bcs bcs suppConductor相一致。尽管这些不明显的超导性能，这些薄膜仍表现出非常高的上层临界场。我们估计他们的零温度$ H_ {C2} $是Pauli限制的两倍以上。实际上，在6 nm样品中，估计的降低临界场$ h_ {c2}/t_c \ sim $ 5.6 t/k是任何元素超导体报告的最高报告之一。尽管膜的电阻远低于量子电阻$ r_q = h/4e^2 $，但它们的$ h_ {c2} $接近了$ k_f \ ell \ ell \ sim1 $的强大无序超导体的理论上极限。
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 $H_{c2}$ to be more than twice the Pauli limit. Indeed, in 6 nm samples the estimated reduced critical field $H_{c2}/T_c\sim$ 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 $R_Q=h/4e^2$, their $H_{c2}$'s approached the theoretical upper limit of a strongly disordered superconductor for which $k_F\ell\sim1$.
