12 research outputs found
Nanopattern-stimulated superconductor-insulator transition in thin TiN films
We present the results of the comparative study of the influence of disorder
on transport properties in continuous and nanoperforated TiN films. We show
that nanopatterning turns a thin TiN film into an array of superconducting weak
links and stimulates both, the disorder- and magnetic field-driven
superconductor-to-insulator transitions, pushing them to lower degree of
disorder. We find that nanopatterning enhances the role of the two-dimensional
Coulomb interaction in the system transforming the originally insulating film
into a more pronounced insulator. We observe magnetoresistance oscillations
reflecting collective behaviour of the multiconnected nanopatterned
superconducting film in the wide range of temperatures and uncover the physical
mechanism of these oscillations as phase slips in superconducting weak link
network.Comment: 6 pages, 4 figure
Nonequilibrium mesoscopic superconductors in a fluctuational regime
We show that there exist a class of nonequilibrium systems for which a
non-equilibrium analog of the Ginzburg-Landau (GL) functional can be
constructed and propose the procedure for its derivation. As an example, we
consider a small superconductor island of the size less than the coherence
length in a stationary nonequlibrium state. We find the GL expansion of the
free energy functional of such a system and analyze the dependence of the
coefficients of the expansion upon the external drive and the non-equilibrium
distribution functions.Comment: 5 pages, 1 figur
Stimulation of the fluctuation superconductivity by the PT-symmetry
We discuss fluctuations near the second order phase transition where the free
energy has an additional non-Hermitian term. The spectrum of the fluctuations
changes when the odd-parity potential amplitude exceeds the critical value
corresponding to the PT-symmetry breakdown in the topological structure of the
Hilbert space of the effective non-Hermitian Hamiltonian. We calculate the
fluctuation contribution to the differential resistance of a superconducting
weak link and find the manifestation of the PT-symmetry breaking in its
temperature evolution. We successfully validate our theory by carrying out
measurements of far from equilibrium transport in mesoscale-patterned
superconducting wires.Comment: Phys. Rev. Lett 201
Far-from-equilibrium superconductor in fluctuational regime
12 pages, 5 figuresInternational audienceWe derive Ginzburg-Landau-like action for two-dimensional disordered superconductor under far-from-equilibrium conditions in a fluctuational regime. Then, utilizing it, we calculate fluctuation induced density of states, Maki-Thomson and Aslamazov-Larkin type contributions to the in-plane electrical conductivity. We apply our approach to thin superconducting film sandwiched between a gate and a substrate that have different temperatures and different electrochemical potentials