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A quantum wire is spatially displaced by suitable electric fields with respect to the scatterers inside a semiconductor crystal. As a function of the wire position, the low-temperature resistance shows reproducible fluctuations. Their…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 T. Heinzel , G. Salis , R. Held , S. Luescher , K. Ensslin , W. Wegscheider , M. Bichler

Thermal fluctuations of the order parameter in an ultrathin triangular shaped superconducting structure are studied near $T_{c}$, in zero applied field. We find that the order parameter is prone to much larger fluctuations in the corners of…

Superconductivity · Physics 2010-09-06 W. V. Pogosov , V. R. Misko , F. M. Peeters

We have patterned a hexagonal array of nano-scale holes into a series of ultrathin, superconducting Bi/Sb films with transition temperatures 2.65 K $<T_{co} < $5 K. These regular perforations give the films a phase-sensitive periodic…

Superconductivity · Physics 2009-11-11 M. D. Stewart , Zhenyi Long , James M. Valles , Aijun Yin , J. M. Xu

We investigate the effect of interacting quantum phase slips on persistent current and its fluctuations in ultrathin superconducting nanowires and nanorings pierced by the external magnetic flux. We derive the effective action for these…

Mesoscale and Nanoscale Physics · Physics 2013-09-02 Andrew G. Semenov , Andrei D. Zaikin

Superconducting nanowires undergoing quantum phase-slips have potential for impact in electronic devices, with a high-accuracy quantum current standard among a possible toolbox of novel components. A key element of developing such…

Superconductivity · Physics 2018-06-21 N. G. N. Constantino , M. S. Anwar , O. W. Kennedy , M. Dang , P. A. Warburton , J. C. Fenton

We study the order parameter phase fluctuation effects in cuprate superconductors near T=0, using a quasi-two-dimensional d-wave BCS model. An effective phason theory is obtained which is used to estimate the strength of the fluctuations,…

Superconductivity · Physics 2009-10-31 Hyok-Jon Kwon , Alan T. Dorsey , P. J. Hirschfeld

We investigate the role of quantum effects (e.g. zero-point energy fluctuations) in the physics of nanotube- and nanowire-based electromechanical sensors as discussed in a recent article [Postma et al., Appl. Phys. Lett. 86, 223105 (2005)].…

Materials Science · Physics 2007-05-23 Christoph Stampfer , Stefan Rotter , Joachim Burgdoerfer

We present the first study of superconducting nanowires shunted with an external resistor, geared towards understanding and controlling coherence and dissipation in nanowires. The dynamics is probed by measuring the evolution of the V-I…

Mesoscale and Nanoscale Physics · Physics 2012-09-14 Matthew W. Brenner , Dibyendu Roy , Nayana Shah , Alexey Bezryadin

We study the rate of quantum phase slips in an ultranarrow superconducting nanowire exposed to weak electromagnetic radiations. The superconductor is in the dirty limit close to the superconducting-insulating transition, where fluxoids move…

Mesoscale and Nanoscale Physics · Physics 2015-07-13 Amir Jafari-Salim , Amin Eftekharian , A. Hamed Majedi , Mohammad H. Ansari

The effect of fluctuation induced weakly first order phase transition known for three dimensional (3D) type I superconductors appears in a modified and strongly enhanced variant in thin (quasi-2D) superconducting films. The unusual…

Superconductivity · Physics 2009-11-07 R. Folk , D. V. Shopova , D. I. Uzunov

We study the combined effect of thermal and quantum fluctuations in a zero dimensional superconductor. By using path integral techniques, we obtain novel expressions for the partition function and the superconducting order parameter which…

Superconductivity · Physics 2012-04-05 Pedro Ribeiro , Antonio M. García-García

The magnetization around the superconducting transition was measured in a Tl$_{0.5}$Pb$_{0.5}$Sr$_2$CaCu$_2$O$_7$ crystal affected by a considerable reduction ($\sim$55%) of its effective superconducting volume fraction but still with a…

Superconductivity · Physics 2009-11-13 Jesús Mosqueira , Félix Vidal

Based on the recent free electron model for cohesion in narrow metallic constrictions by Stafford et al., we calculate the quantum fluctuations in the cohesive force versus elongation. The fluctuations are dominated by states near the Fermi…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 C. Hoeppler , W. Zwerger

We present results from an extensive study of fluctuation phenomena in superconducting nanowires made from sputtered NbN. Nanoscale wires were fabricated in form of a meander and operated at a constant temperature T~0.4Tc(0). The…

Superconductivity · Physics 2014-11-20 H. Bartolf , A. Engel , A. Schilling , K. Il'in , M. Siegel , H. -W. Huebers , A. Semenov

We argue that quantum phase slips (QPS) may generate non-equilibrium voltage fluctuations in superconducting nanowires. In the low frequency limit we evaluate all cumulants of the voltage operator which obey Poisson statistics and show a…

Mesoscale and Nanoscale Physics · Physics 2019-01-10 Andrew G. Semenov , Andrei D. Zaikin

Type II superconductors, consisting of superconducting domains embedded in a normal or insulating matrix, undergo a rounded phase transition. Indeed, the correlation length cannot grow beyond the spatial extent of the domains. Accordingly,…

Superconductivity · Physics 2009-11-10 T. Schneider

Conductance fluctuation is usually unavoidable in graphene nanoribbons (GNR) due to the presence of disorder along its edges. By measuring the low-frequency noise in GNR devices, we find that the conductance fluctuation is strongly…

Mesoscale and Nanoscale Physics · Physics 2010-10-12 Guangyu Xu , Carlos M. Torres , Emil B. Song , Jianshi Tang , Jingwei Bai , Xiangfeng Duan , Yuegang Zhang , Kang L. Wang

We theoretically investigate effects of quantum fluctuations on superfluid spin transport through easy-plane quantum antiferromagnetic spin chains in the large-spin limit. Quantum fluctuations give rise to decaying of spin supercurrent by…

Mesoscale and Nanoscale Physics · Physics 2016-03-31 Se Kwon Kim , Yaroslav Tserkovnyak

The effect of negative magnetoresistance for thin superconducting wire was considered in a simple model. These phenomena originated from competition of two mechanism: fluctuations of the order parameter and quasiparticles charge imbalance…

Superconductivity · Physics 2021-01-28 Boris Ya. Shapiro

An important question in the physics of superconducting nanostructures is the role of thermal fluctuations on superconductivity in the zero-dimensional limit. Here, we probe the evolution of superconductivity as a function of temperature…

Mesoscale and Nanoscale Physics · Physics 2011-09-13 Ivan Brihuega , Antonio M. Garcia-Garcia , Pedro Ribeiro , Miguel M. Ugeda , Christian H. Michaelis , Sangita Bose , Klaus Kern