title: Surface superconductivity in thin cylindrical Bi nanowire.
abstract: The physical origin and the nature of superconductivity in nanostructured Bi remains puzzling. Here, we report transport measurements of individual cylindrical single-crystal Bi nanowires, 20 and 32 nm in diameter. In contrast to nonsuperconducting Bi nanoribbons with two flat surfaces, cylindrical Bi nanowires show superconductivity below 1.3 K. However, their superconducting critical magnetic fields decrease with their diameter, which is the opposite of the expected behavior for thin superconducting wires. Quasiperiodic oscillations of magnetoresistance were observed in perpendicular fields but were not seen in the parallel orientation. These results can be understood by a model of surface superconductivity with an enhanced surface-to-bulk volume in small diameter wires, where the superconductivity originates from the strained surface states of the nanowires due to the surface curvature-induced stress.
authors: Center for Nanoscale Science, The Pennsylvania State University , University Park, Pennsylvania 16802-6300, United States.
authors: Mingliang
authors: M
authors: Tian
authors: Jian
authors: J
authors: Wang
authors: Wei
authors: W
authors: Ning
authors: Thomas E
authors: TE
authors: Mallouk
authors: Moses H W
authors: MH
authors: Chan
keywords: Bi nanowires; magnetoresistance; quantum oscillations; surface superconductivity