Scaling structure of attractors at the transition from quasiperiodicity to chaos in electronic transport in Ge

We present a high-precision experimental verification of the universality of f({α}), the fractal dimension of the subset of the attractor with scaling index {α}, at the transition from quasiperiodicity to chaos with the golden-mean winding number. The experimental system is cooled extrinsic p-type Ge, which is voltage biased to produce a spatially dependent active oscillation.