We have fabricated and studied the transport properties of arrays of proximity-coupled superconductor islands arranged in a quasiperiodic Penrose tile geometry. In the magnetic field response, we identify coarse structure arising from the irrational area ratio of the two fundamental tile shapes, and fine structure due to the long-range quasiperiodic order of the array. By varying the voltage bias of the sample, which governs the rate of vortex diffusion, we can adjust the range of phase coherence in the array and identify the origin of specific features in the magnetoresistance. These ideas have been corroborated by measurements on ladder arrays with varying widths and on periodic arrays with two irrationally-related cell areas. Measurements of the resistive transition and nonlinear current-voltage characteristics are consistent with a Kosterlitz-Thouless vortex-unbinding phase transition at zero field, but show more complicated behavior at finite fields.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering