Localization effect in a two-dimensional superconducting network without disorder

Abstract

The superconducting properties of a two-dimensional superconducting wire network with a new geometry have been measured as a function of the external magnetic field. The extreme localization effect recently predicted for this periodic lattice is revealed as a suppression of the critical current when the applied magnetic field corresponds to half a flux quantum per unit cell. For this particular magnetic field, the observed vortex state configuration is highly disordered. PACS[72.15, 73.23, 74.25]

Structure of the superconducting state in a fully frustrated wire network with dice lattice geometry

“…1), the residual entropy is proportional to the system linear size [26], as for the honeycomb lattice. Experimentally, magnetic decoration experiments [24,25] have found a highly disordered vortex pattern, with a vortex correlation length comparable to the lattice spacing. Numerical simulations [27] of the corresponding XY model support the picture proposed in Ref.…”

Landau levels in the case of two degenerate coupled bands: Kagomé lattice tight-binding spectrum

“…The magnetic-field-induced frustration in two-dimensional structures has also been a subject of active experimental study using superconducting wire networks 2,3 , as the linearized Ginzburg-Landau equation for the superconductor and the Schrodinger equation for the tight-binding electron wavefunction in these lattices share the same form 4 . The investigation of a variety of structures, such as the triangular lattice 5 , the honeycomb lattice 6 , and recently the T 3 or dice lattice 7,8 , has revealed the richness and the beauty of physics in these systems.…”

Glassy dynamics of Josephson arrays on a dice lattice

“…In the case of superconducting wire networks the existence of the AB cages manifests in a suppression of the critical current and of the superconducting critical temperature when the dice network is fully frustrated [2,4]. Unexpectedly, decoration espriments [5,6] have shown that those localization effects are accompanied by the absence of any regular pattern in the low temperature vortex configuration Together with wire networks, Josephson Junction Arrays (JJA) [7], i.e. networks of superconducting islands connected through Josephson junctions, are ideal systems where to investigate subtle effects induced by the lattice structure and applied magnetic field are.…”

“…Among those works a large body of activity has been devoted to the study of frustration induced by a magnetic field applied perpendicularly to the array [9]. As in the case of wire networks [2,5,6], one expects that the superconducting transition temperature for JJA would signal the presence of localization. Contrary to wire networks however, phase fluctuations, described by the two-dimensional XY model, will play a dominant role.…”