Size matters: nanoscale superconductors and beyond. Zhili Xiao. When the
charge carriers – Cooper pairs in a superconductor are squeezed into a small ...
Size matters: nanoscale superconductors and beyond Zhili Xiao When the charge carriers – Cooper pairs in a superconductor are squeezed into a small volume comparable to the superconducting coherence length or penetration depth, their wave functions and distribution of the magnetic field will be strongly modified. Therefore, nanoscale superconductors are expected to exhibit properties different from bulk materials. This colloquium will give an overview on our research projects on nanostructured superconductors. We utilized existing and/or developed new approaches to synthesize nanostructured superconductors and explored their properties. Examples include the confinement-induced change in the anisotropy of niobium (Nb) nano-strips and films containing arrays of nanoscale holes [1,2], large magnetoresistance oscillations in nanoscale Nb strips with a chain of holes [3], and the realization of vortex ices [4] in patterned molybdenum germanium (MoGe) films. In addition to the fundamental research on nanoscale superconductors, I will report recent progresses on our applied nanoresearch project – nanomaterials based hydrogen sensors [5]. I will also briefly introduce our new projects on topological insulators [6], graphenes, and smart window materials.
Relevant publications 1. J. Hua, Z. L. Xiao, A. Imre, S. H. Yu, U. Patel, L. E. Ocola, R. Divan, A. Koshelev, J. Pearson, U. Welp, and W. K. Kwok, Magnetoresistance anisotropy of a one-dimensional superconducting niobium strip, Physical Review Letters 101, 077003 (2008). 2. M. L. Latimer, Z. L. Xiao, J. Hua, A. Joshi-Imre, Y. L. Wang, R. Divan, W. K. Kwok, and G. W. Crabtree, Anisotropy of the critical temperature of a superconducting niobium thin film with an array of nanoscale holes in an external magnetic field, Physical Review B 87, (Rapid Communication) 020507 (2013). 3. G. R. Berdiyorov, M. V. Milosevic, M. L. Latimer, Z. L. Xiao, W. K. Kwok, and F. M. Peeters, Large magnetoresistance oscillations in mesoscopic superconductors due to current-excited moving vortices, Physical Review Letters 109, 057004 (2012). 4. M. L. Latimer, G. R. Berdiyorov, Z. L. Xiao, F. M. Peeters, and W. K. Kwok, Realization of artificial ice systems for magnetic vortices in a superconducting MoGe thin film with patterned nanostructures, Physical Review Letters 111, 067001 (2013). 5. X. Q. Zeng, M. L. Latimer, Z. L. Xiao, S. Panuganti, U. Welp, W. K. Kwok, and T. Xu, Hydrogen Gas Sensing With Networks of Ultra-small Palladium Nanowires Formed on Filtration Membranes, Nano Letters 11, 262 (2011). 6. L. Fang, Y. Jia, D. J. Miller, M. L. Latimer, Z. L. Xiao, U. Welp, G. W. Crabtree, and W. -K. Kwok, Catalyst-free growth of millimeter-long topological insulator Bi2Se3 nanoribbons and the observation of the π-Berry phase, Nano Letters 12, 6164 (2012).
