Department of Physics and the William Mong Institute of Nano Science and Technology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China.
ACS Nano. 2013 May 28;7(5):4187-93. doi: 10.1021/nn400604v. Epub 2013 Apr 12.
We have produced ultrathin lead (Pb) nanowires in the 6 nm pores of SBA-15 mesoporous silica substrates by chemical vapor deposition. The nanowires form regular and dense arrays. We demonstrate that bulk Pb (a type-I superconductor below Tc = 7.2 K with a critical field of 800 Oe) can be tailored by nanostructuring to become a type-II superconductor with an upper critical field (Hc2) exceeding 15 T and signs of Cooper pairing 3-4 K above the bulk Tc. The material undergoes a crossover from a one-dimensional fluctuating superconducting state at high temperatures to three-dimensional long-range-ordered superconductivity in the low-temperature regime. We show with our data in an impressive way that superconductivity in elemental metals can be greatly enhanced by nanostructuring.
我们通过化学气相沉积在 SBA-15 介孔硅基底的 6nm 孔中制备出了超薄的铅（Pb）纳米线。这些纳米线形成了规则而密集的阵列。我们证明，块状铅（在 Tc=7.2K 以下为第一类超导体，临界场为 800Oe）通过纳米结构化可以变成具有上临界场（Hc2）超过 15T 的第二类超导体，并且在块状 Tc 之上 3-4K 处出现库珀配对的迹象。该材料在高温下从一维波动超导态转变为低温下的三维长程有序超导态。我们的数据令人信服地表明，元素金属的超导性可以通过纳米结构化得到极大增强。
