The effects of random dilution of junctions on a two-dimensional Josephson-junction array in a magnetic field are considered. For rational values of the average flux quantum per plaquette $f$, the superconducting transition temperature vanishes, for increasing dilution, at a critical value $x_S(f)$, while the vortex ordering remains stable up to $x_{ VL}>x_S$, much below the value $x_p$ corresponding to the geometric percolation threshold. For $ x_{ VL}<x<x_p$, the array behaves as a zero-temperature vortex-glass. Numerical results for $f=1/2$ from defect energy calculations are presented which are consistent with this scenario.
Categories: cond-mat.supr-con